@article{pmid10760259,

title = {Using antibody catalysis to study the outcome of multiple evolutionary trials of a chemical task},

author = {A Karlstrom and G Zhong and C Rader and N A Larsen and A Heine and R Fuller and B List and F Tanaka and I A Wilson and C F Barbas and R A Lerner},

doi = {10.1073/pnas.97.8.3878},

issn = {0027-8424},

year  = {2000},

date = {2000-04-01},

journal = {Proc Natl Acad Sci U S A},

volume = {97},

number = {8},

pages = {3878--3883},

abstract = {Catalytic aldolase antibodies generated by immunization with two different, but structurally related, beta-diketone haptens were cloned and sequenced to study similarities and differences between independently evolved catalysts. Kinetic and sequence analysis coupled with mutagenesis, structural, and modeling studies reveal that the defining event in the evolution of these catalysts was a somatic mutation that placed a lysine residue in a deep, yet otherwise unrefined, hydrophobic pocket. We suggest that covalent chemistries may be as readily selected from the immune repertoire as the traditional noncovalent interactions that have formed the basis of immunochemistry until this time. Further, we believe that these experiments recapitulate the defining events in the evolution of nature's enzymes, particularly as they relate to chemical mechanism, catalytic promiscuity, and gene duplication.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10755612,

title = {A functional hot spot for antigen recognition in a superagonist TCR/MHC complex},

author = {M Degano and K C Garcia and V Apostolopoulos and M G Rudolph and L Teyton and I A Wilson},

doi = {10.1016/s1074-7613(00)80178-8},

issn = {1074-7613},

year  = {2000},

date = {2000-03-01},

journal = {Immunity},

volume = {12},

number = {3},

pages = {251--261},

abstract = {A longstanding question in T cell receptor signaling is how structurally similar ligands, with similar affinities, can have substantially different biological activity. The crystal structure of the 2C TCR complex of H-2Kb with superagonist peptide SIYR at 2.8 A elucidates a structural basis for TCR discrimination of altered peptide ligands. The difference in antigen potency is modulated by two cavities in the TCR combining site, formed mainly by CDRs 3alpha, 3beta, and 1beta, that complement centrally located peptide residues. This "functional hot spot" allows the TCR to finely discriminate amongst energetically similar interactions within different ligands for those in which the peptide appropriately stabilizes the TCR/pMHC complex and provides a new structural perspective for understanding differential signaling resulting from T cell cross-reactivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid11208110,

title = {A new functional domain of guanine nucleotide dissociation inhibitor (alpha-GDI) involved in Rab recycling},

author = {P Luan and A Heine and K Zeng and B Moyer and S E Greasely and P Kuhn and W E Balch and I A Wilson},

doi = {10.1034/j.1600-0854.2000.010309.x},

issn = {1398-9219},

year  = {2000},

date = {2000-03-01},

journal = {Traffic},

volume = {1},

number = {3},

pages = {270--281},

abstract = {Guanine nucleotide dissociation inhibitor (GDI) is a 55-kDa protein that functions in vesicular membrane transport to recycle Rab GTPases. We have now determined the crystal structure of bovine alpha-GDI at ultra-high resolution (1.04 A). Refinement at this resolution highlighted a region with high mobility of its main-chain residues. This corresponded to a surface loop in the primarily alpha-helical domain II at the base of alpha-GDI containing the previously uncharacterized sequence-conserved region (SCR) 3A. Site-directed mutagenesis showed that this mobile loop plays a crucial role in binding of GDI to membranes and extraction of membrane-bound Rab. This domain, referred to as the mobile effector loop, in combination with Rab-binding residues found in the multi-sheet domain I at the apex of alpha-GDI may provide flexibility for recycling of diverse Rab GTPases. We propose that conserved residues in domains I and II synergize to form the functional face of GDI, and that domain II mediates a critical step in Rab recycling during vesicle fusion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid11249650,

title = {Structural implications for the design of molecular vaccines},

author = {V Apostolopoulos and M Yu and I F McKenzie and I A Wilson},

issn = {1464-8431},

year  = {2000},

date = {2000-02-01},

journal = {Curr Opin Mol Ther},

volume = {2},

number = {1},

pages = {29--36},

abstract = {The major histocompatibility complex molecules bind and present short antigenic peptide fragments on the surface of antigen presenting cells to T-cell receptors. Recognition of peptide-MHC by cytotoxic T-cells initiates a cascade of signals to T-cells, which in turn destroy the antigen presenting cell. In the design of molecular vaccines for the treatment of diseases, an understanding of the 3-dimensional structure of MHC class I and is interaction with both peptide and T-cell receptor is an important prerequisite. In this review, we will discuss such crystal structures, as well as structures of glycopeptides and alternative T-cell antigens presented by MHC molecules.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10634787,

title = {Crystal structure of a gammadelta T cell receptor ligand T22: a truncated MHC-like fold},

author = {C Wingren and M P Crowley and M Degano and Y Chien and I A Wilson},

doi = {10.1126/science.287.5451.310},

issn = {0036-8075},

year  = {2000},

date = {2000-01-01},

journal = {Science},

volume = {287},

number = {5451},

pages = {310--314},

abstract = {Murine T10 and T22 are highly related nonclassical major histocompatibility complex (MHC) class Ib proteins that bind to certain gammadelta T cell receptors (TCRs) in the absence of other components. The crystal structure of T22b at 3.1 angstroms reveals similarities to MHC class I molecules, but one side of the normal peptide-binding groove is severely truncated, which allows direct access to the beta-sheet floor. Potential gammadelta TCR-binding sites can be inferred from functional mapping of T10 and T22 point mutants and allelic variants. Thus, T22 represents an unusual variant of the MHC-like fold and indicates that gammadelta and alphabeta TCRs interact differently with their respective MHC ligands.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10606510,

title = {New insights into inhibitor design from the crystal structure and NMR studies of Escherichia coli GAR transformylase in complex with beta-GAR and 10-formyl-5,8,10-trideazafolic acid},

author = {S E Greasley and M M Yamashita and H Cai and S J Benkovic and D L Boger and I A Wilson},

doi = {10.1021/bi991888a},

issn = {0006-2960},

year  = {1999},

date = {1999-12-01},

journal = {Biochemistry},

volume = {38},

number = {51},

pages = {16783--16793},

abstract = {The crystal structure of Escherichia coli GAR Tfase at 2.1 A resolution in complex with 10-formyl-5,8,10-trideazafolic acid (10-formyl-TDAF, K(i) = 260 nM), an inhibitor designed to form an enzyme-assembled multisubstrate adduct with the substrate, beta-GAR, was studied to determine the exact nature of its inhibitory properties. Rather than forming the expected covalent adduct, the folate inhibitor binds as the hydrated aldehyde (gem-diol) in the enzyme active site, in a manner that mimics the tetrahedral intermediate of the formyl transfer reaction. In this hydrated form, the inhibitor not only provides unexpected insights into the catalytic mechanism but also explains the 10-fold difference in inhibitor potency between 10-formyl-TDAF and the corresponding alcohol, and a further 10-fold difference for inhibitors that lack the alcohol. The presence of the hydrated aldehyde was confirmed in solution by (13)C-(1)H NMR spectroscopy of the ternary GAR Tfase-beta-GAR-10-formyl-TDAF complex using the (13)C-labeled 10-formyl-TDAF. This insight into the behavior of the inhibitor, which is analogous to protease or transaminase inhibitors, provides a novel and previously unrecognized basis for the design of more potent inhibitors of the folate-dependent formyl transfer enzymes of the purine biosynthetic pathway and development of anti-neoplastic agents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10600746,

title = {Evolution of shape complementarity and catalytic efficiency from a primordial antibody template},

author = {J Xu and Q Deng and J Chen and K N Houk and J Bartek and D Hilvert and I A Wilson},

doi = {10.1126/science.286.5448.2345},

issn = {0036-8075},

year  = {1999},

date = {1999-12-01},

journal = {Science},

volume = {286},

number = {5448},

pages = {2345--2348},

abstract = {The crystal structure of an efficient Diels-Alder antibody catalyst at 1.9 angstrom resolution reveals almost perfect shape complementarity with its transition state analog. Comparison with highly related progesterone and Diels-Alderase antibodies that arose from the same primordial germ line template shows the relatively subtle mutational steps that were able to evolve both structural complementarity and catalytic efficiency.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10610577,

title = {Perspectives: protein structure. Class-conscious TCR?},

author = {I A Wilson},

doi = {10.1126/science.286.5446.1867},

issn = {0036-8075},

year  = {1999},

date = {1999-12-01},

journal = {Science},

volume = {286},

number = {5446},

pages = {1867--1868},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10607675,

title = {The structure, organization, activation and plasticity of the erythropoietin receptor},

author = {I A Wilson and L K Jolliffe},

doi = {10.1016/s0959-440x(99)00032-9},

issn = {0959-440X},

year  = {1999},

date = {1999-12-01},

journal = {Curr Opin Struct Biol},

volume = {9},

number = {6},

pages = {696--704},

abstract = {Dimerization of the erythropoietin receptor has long been accepted as the singular step in its mechanism of activation. Recent studies have revealed a regulator process for activation that is dependent on the actual configuration of the receptor-ligand dimer assembly. This aspect of the receptor subunit assembly appears to extend to the unliganded receptor, which can dimerize on the cell surface and diminish any spontaneous background signaling in the absence of ligand. This self-recognition, as well as the multiple ligand binding capabilities of the receptor binding site, is consistent with an emerging theme of plasticity in protein-protein and ligand-receptor interactions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10631954,

title = {The molecular basis of CD1-mediated presentation of lipid antigens},

author = {D B Moody and G S Besra and I A Wilson and S A Porcelli},

doi = {10.1111/j.1600-065x.1999.tb01373.x},

issn = {0105-2896},

year  = {1999},

date = {1999-12-01},

journal = {Immunol Rev},

volume = {172},

pages = {285--296},

abstract = {The CD1 family of proteins mediates a newly described pathway for presentation of lipids and glycolipids for specific recognition by T cells. All four of the known human CD1 proteins (CD1a, CD1b, CD1c and CD1d) as well as murine CD1d have now been shown to mediate T-cell recognition of lipid or glycolipid antigens. These antigens include naturally occurring foreign glycolipids from intracellular pathogens or synthetic glycolipids that are related in structure to mammalian glycolipids. The CD1b and CD1d-presented antigens differ in their fine structures but reveal a general motif in which a rigid hydrophilic cap is bound to two aliphatic hydrocarbon chains. Different T-cell populations recognize individual antigens without cross-reactivity to closely related antigen structures or CD1 isoforms, documenting the complexity and fine specificity of CD1-mediated T-cell responses. Mapping of the molecular determinants of recognition for CD1b and CD1d-presented antigens reveals that T cells discriminate the fine structure of the hydrophilic cap of the antigen, but both the length and structure of the lipid chains may be altered without loss of recognition. This pattern of lipid antigen recognition may be accounted for by a simple molecular mechanism of presentation that parallels the known mechanism for presentation of peptides, but solves the special problems related to the hydrophobic chemical nature of the lipid antigens. We propose that CD1 binds antigen by accommodating the two lipid tails within the hydrophobic groove of its two membrane distal domains, positioning the rigid hydrophilic cap of the antigen on the solvent-exposed surface of the CD1 protein, where it can directly contact the T-cell antigen receptor. This model provides a molecular basis for recognition of a new and diverse set of T-cell antigens contained within the lipid bilayers of cellular membranes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10529350,

title = {Roles for glycosylation of cell surface receptors involved in cellular immune recognition},

author = {P M Rudd and M R Wormald and R L Stanfield and M Huang and N Mattsson and J A Speir and J A DiGennaro and J S Fetrow and R A Dwek and I A Wilson},

doi = {10.1006/jmbi.1999.3104},

issn = {0022-2836},

year  = {1999},

date = {1999-10-01},

journal = {J Mol Biol},

volume = {293},

number = {2},

pages = {351--366},

abstract = {The majority of cell surface receptors involved in antigen recognition by T cells and in the orchestration of the subsequent cell signalling events are glycoproteins. The length of a typical N-linked sugar is comparable with that of an immunoglobulin domain (30 A). Thus, by virtue of their size alone, oligosaccharides may be expected to play a significant role in the functions and properties of the cell surface proteins to which they are attached. A databank of oligosaccharide structures has been constructed from NMR and crystallographic data to aid in the interpretation of crystal structures of glycoproteins. As unambiguous electron density can usually only be assigned to the glycan cores, the remainder of the sugar is then modelled into the crystal lattice by superimposing the appropriate oligosaccharide from the database. This approach provides insights into the roles that glycosylation might play in cell surface receptors, by providing models that delineate potential close packing interactions on the cell surface. It has been proposed that the specific recognition of antigen by T cells results in the formation of an immunological synapse between the T cell and the antigen-presenting cell. The cell adhesion glycoproteins, such as CD2 and CD48, help to form a cell junction, providing a molecular spacer between opposing cells. The oligosaccharides located on the membrane proximal domains of CD2 and CD48 provide a scaffold to orient the binding faces, which leads to increased affinity. In the next step, recruitment of the peptide major histocompatibility complex (pMHC) by the T-cell receptors (TCRs) requires mobility on the membrane surface. The TCR sugars are located such that they could prevent non-specific aggregation. Importantly, the sugars limit the possible geometry and spacing of TCR/MHC clusters which precede cell signalling. We postulate that, in the final stage, the sugars could play a general role in controlling the assembly and stabilisation of the complexes in the synapse and in protecting them from proteolysis during prolonged T-cell engagement.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10353817,

title = {Structural basis for antibody catalysis of a disfavored ring closure reaction},

author = {K Gruber and B Zhou and K N Houk and R A Lerner and C G Shevlin and I A Wilson},

doi = {10.1021/bi990210s},

issn = {0006-2960},

year  = {1999},

date = {1999-06-01},

journal = {Biochemistry},

volume = {38},

number = {22},

pages = {7062--7074},

abstract = {The catalysis of disfavored chemical reactions, especially those with no known natural enzyme counterparts, is one of the most promising achievements of catalytic antibody research. Antibodies 5C8, 14B9, 17F6, and 26D9, elicited by two different transition-state analogues, catalyze disfavored endo-tet cyclization reactions of trans-epoxy alcohols, in formal violation of Baldwin's rules for ring closure. Thus far, neither chemical nor enzyme catalysis has been capable of emulating the extraordinary activity and specificity of these antibodies. X-ray structures of two complexes of Fab 5C8 with the original hapten and with an inhibitor have been determined to 2.0 A resolution. The Fab structure has an active site that contains a putative catalytic diad, consisting of AspH95 and HisL89, capable of general acid/base catalysis. The stabilization of a positive charge that develops along the reaction coordinate appears to be an important factor for rate enhancement and for directing the reaction along the otherwise disfavored pathway. Sequence analysis of the four catalytic antibodies, as well as four inactive antibodies that strongly bind the transition-state analogues, suggests a conserved catalytic mechanism. The occurrence of the putative base HisL89 in all active antibodies, its absence in three out of the four analyzed inactive antibodies, and the rarity of a histidine at this position in immunoglobulins support an important catalytic role for this residue.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10318834,

title = {Shared and unique determinants of the erythropoietin (EPO) receptor are important for binding EPO and EPO mimetic peptide},

author = {S A Middleton and F P Barbone and D L Johnson and R L Thurmond and Y You and F J McMahon and R Jin and O Livnah and J Tullai and F X Farrell and M A Goldsmith and I A Wilson and L K Jolliffe},

doi = {10.1074/jbc.274.20.14163},

issn = {0021-9258},

year  = {1999},

date = {1999-05-01},

journal = {J Biol Chem},

volume = {274},

number = {20},

pages = {14163--14169},

abstract = {We have shown previously that Phe93 in the extracellular domain of the erythropoietin (EPO) receptor (EPOR) is crucial for binding EPO. Substitution of Phe93 with alanine resulted in a dramatic decrease in EPO binding to the Escherichia coli-expressed extracellular domain of the EPOR (EPO-binding protein or EBP) and no detectable binding to full-length mutant receptor expressed in COS cells. Remarkably, Phe93 forms extensive contacts with a peptide ligand in the crystal structure of the EBP bound to an EPO-mimetic peptide (EMP1), suggesting that Phe93 is also important for EMP1 binding. We used alanine substitution of EBP residues that contact EMP1 in the crystal structure to investigate the function of these residues in both EMP1 and EPO binding. The three largest hydrophobic contacts at Phe93, Met150, and Phe205 and a hydrogen bonding interaction at Thr151 were examined. Our results indicate that Phe93 and Phe205 are important for both EPO and EMP1 binding, Met150 is not important for EPO binding but is critical for EMP1 binding, and Thr151 is not important for binding either ligand. Thus, Phe93 and Phe205 are important binding determinants for both EPO and EMP1, even though these ligands share no sequence or structural homology, suggesting that these residues may represent a minimum epitope on the EPOR for productive ligand binding.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10368281,

title = {Dual conformations for the HIV-1 gp120 V3 loop in complexes with different neutralizing fabs},

author = {R Stanfield and E Cabezas and A Satterthwait and E Stura and A Profy and I Wilson},

doi = {10.1016/s0969-2126(99)80020-3},

issn = {0969-2126},

year  = {1999},

date = {1999-02-01},

journal = {Structure},

volume = {7},

number = {2},

pages = {131--142},

abstract = {BACKGROUND: The third hypervariable (V3) loop of HIV-1 gp120 has been termed the principal neutralizing determinant (PND) of the virus and is involved in many aspects of virus infectivity. The V3 loop is required for viral entry into the cell via membrane fusion and is believed to interact with cell surface chemokine receptors on T cells and macrophages. Sequence changes in V3 can affect chemokine receptor usage, and can, therefore, modulate which types of cells are infected. Antibodies raised against peptides with V3 sequences can neutralize laboratory-adapted strains of the virus and inhibit syncytia formation. Fab fragments of these neutralizing antibodies in complex with V3 loop peptides have been studied by X-ray crystallography to determine the conformation of the V3 loop.



RESULTS: We have determined three crystal structures of Fab 58.2, a broadly neutralizing antibody, in complex with one linear and two cyclic peptides the amino acid sequence of which comes from the MN isolate of the gp120 V3 loop. Although the peptide conformations are very similar for the linear and cyclic forms, they differ from that seen for the identical peptide bound to a different broadly neutralizing antibody, Fab 59.1, and for a similar peptide bound to the MN-specific Fab 50.1. The conformational difference in the peptide is localized around residues Gly-Pro-Gly-Arg, which are highly conserved in different HIV-1 isolates and are predicted to adopt a type II beta turn.



CONCLUSIONS: The V3 loop can adopt at least two different conformations for the highly conserved Gly-Pro-Gly-Arg sequence at the tip of the loop. Thus, the HIV-1 V3 loop has some inherent conformational flexibility that may relate to its biological function.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10358763,

title = {Structural basis of T cell recognition},

author = {K C Garcia and L Teyton and I A Wilson},

doi = {10.1146/annurev.immunol.17.1.369},

issn = {0732-0582},

year  = {1999},

date = {1999-01-01},

journal = {Annu Rev Immunol},

volume = {17},

pages = {369--397},

abstract = {Exciting breakthroughs in the last two years have begun to elucidate the structural basis of cellular immune recognition. Crystal structures have been determined for full-length and truncated forms of alpha beta T cell receptor (TCR) heterodimers, both alone and in complex with their peptide-MHC (pMHC) ligands or with anti-TCR antibodies. In addition, a truncated CD8 coreceptor has been visualized with a pMHC. Aided in large part by the substantial body of knowledge accumulated over the last 25 years on antibody structure, a number of general conclusions about TCR structure and its recognition of antigen can already be derived from the relatively few TCR structures that have been determined. Small, but important, variations between TCR and antibody structures bear on their functional differences as well as on their specific antigen recognition requirements. As observed in antibodies, canonical CDR loop structures are already emerging for some of the TCR CDR loops. Highly similar docking orientations of the TCR V alpha domains in the TCR/pMHC complex appear to play a primary role in dictating orientation, but the V beta positions diverge widely. Similar TCR contact positions, but whose exact amino acid content can vary, coupled with relatively poor interface shape complementarity, may explain the flexibility and short half-lives of many TCR interactions with pMHC. Here we summarize the current state of this field, and suggest that the knowledge gap between the three-dimensional structure and the signaling function of the TCR can be bridged through a synthesis of molecular biological and biophysical techniques.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid10023770,

title = {Crystal structure of an MHC class I presented glycopeptide that generates carbohydrate-specific CTL},

author = {J A Speir and U M Abdel-Motal and M Jondal and I A Wilson},

doi = {10.1016/s1074-7613(00)80006-0},

issn = {1074-7613},

year  = {1999},

date = {1999-01-01},

journal = {Immunity},

volume = {10},

number = {1},

pages = {51--61},

abstract = {T cell receptor (TCR) recognition of nonpeptidic and modified peptide antigens has been recently uncovered but is still poorly understood. Immunization with an H-2Kb-restricted glycopeptide RGY8-6H-Gal2 generates a population of cytotoxic T cells that express both alpha/beta TCR, specific for glycopeptide, and gamma/delta TCR, specific for the disaccharide, even on glycolipids. The crystal structure of Kb/RGY8-6H-Gal2 now demonstrates that the peptide and H-2Kb structures are unaffected by the peptide glycosylation, but the central region of the putative TCR binding site is dominated by the extensive exposure of the tethered carbohydrate. These features of the Kb/RGY8-6H-Gal2 structure are consistent with the individual ligand binding preferences identified for the alpha/beta and gamma/delta TCRs and thus explain the generation of a carbohydrate-specific T cell response.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid11256574,

title = {Emerging principles for T cell receptor recognition of antigen in cellular immunity},

author = {K C Garcia and M Degano and J A Speir and I A Wilson},

issn = {1398-1714},

year  = {1999},

date = {1999-01-01},

journal = {Rev Immunogenet},

volume = {1},

number = {1},

pages = {75--90},

abstract = {The structural basis of antigen recognition in cellular immunity has been elucidated through the determination of crystal structures of major histocompatibility complex (MHC) molecules bound to antigenic peptides, T cell receptors (TCR), CD8 and CD4 co-receptors and, most recently, TCRs in complex with peptide-MHC (pMHC). The mechanisms that generate the diversity of the immune response to invading microorganisms were first realized at a genetic level and are necessary in order to cope with the enormous number of potential antigens. This diversity is manifested in the protein products of the genes which code for the components of the TCR signalling complex. The structure of the TCR reveals both striking similarities with and fundamental differences from its functional counterpart, the antibody, in the humoral immune system. The conserved manner in which the TCR recognizes and interacts with its peptide-MHC ligand allows the TCR great latitude in its potential to form productive interactions with antigen-presenting cells that bear numerous ligands to which the TCR has not been previously exposed. This phenomenon of cross-, or alloreactivity arises from a combination of conserved structural features across all MHC molecules, both self and foreign, and some degree of molecular mimicry. Non-classical MHC ligands presenting either modified or specialized peptides, lipids, carbohydrates, or no ligand at all, are now thought to play increasingly important roles in cellular immunity. We review some of the recent structural results and our current state of knowledge about TCR structure, and how this relates to its function.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid15299400,

title = {Reverse screening},

author = {E A Stura and A C Satterthwait and J C Calvo and D C Kaslow and I A Wilson},

doi = {10.1107/S0907444994001794},

issn = {0907-4449},

year  = {1994},

date = {1994-07-01},

journal = {Acta Crystallogr D Biol Crystallogr},

volume = {50},

number = {Pt 4},

pages = {448--455},

abstract = {Major emphasis has been placed in recent years on kits for screening crystallization conditions of macromolecules. Such approaches have undoubtedly speeded up the initial screening and, to a certain extent, helped in reducing the amount of protein required for the initial survey. Factorial screening techniques, either full-factorial or sparse-matrix approaches, have proved successful in the crystallization of many proteins. However, in cases where the amount of protein is limited a systematic approach based on an a priori choice of precipitants may be preferable to an extensive search. The approach described here targets such situations. The approach consists of the determination of the solubility characteristics of the macromolecule under study as a function of precipitant and macromolecule concentrations to define a working range for these parameters. Conditions under which the protein is highly supersaturated, and hence more conducive to nucleation, are established so as to favor the formation of an initial stable nucleus which can be one of the dominant problems that hinders successful crystallization of proteins. Later, changes in solubility as a function of pH and as a result of the introduction of additives are evaluated. In addition, when ligands are available for the formation of macromolecular complexes, screening of different complexes is used as a means to increase the probability of obtaining crystals. Solubility information derived from one, or more, complexes that have been screened can be used for comparison and to aid in the crystallization of other complexes. Cross-seeding between complexes is an intrinsic part of the method and provides an efficient way of obtaining crystals when spontaneous nucleation is hard to achieve. In the example presented here, reverse screening has enabled the production of crystals of several peptide complexes with an anti-malaria antibody.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid11358396,

title = {The hHFE gene of browsing and grazing rhinoceroses: a possible site of adaptation to a low-iron diet},

author = {E Beutler and C West and J A Speir and I A Wilson and M Worley},

doi = {10.1006/bcmd.2001.0386},

issn = {1079-9796},

journal = {Blood Cells Mol Dis},

volume = {27},

number = {1},

pages = {342--350},

abstract = {When rhinoceros species that are browsers in the wild are fed in captivity they become iron overloaded. Presumably, their iron-absorptive mechanisms have evolved to become highly efficient. In humans, mutations of the HFE gene cause increased iron absorption. To determine whether the HFE gene of rhinoceroses has undergone mutation as an adaptive mechanism to improve iron absorption from iron-poor diets, we have sequenced the entire coding region of the HFE genes of four species of rhinoceros. Two of these were browsing species and two were grazing species. Although the HFE gene has been well preserved across species, numerous nucleotide differences were found between rhinoceros and human or mouse, some of which changed deduced amino acids. Of these mutations, only one found in the black rhinoceros appears to be a viable candidate mutation that might adversely affect HFE function. This mutation, S88T, is in a highly conserved region that is involved in the interaction between transferrin receptor and HFE.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid33957119,

title = {50 Years of structural immunology},

author = {Ian A Wilson and Robyn L Stanfield},

doi = {10.1016/j.jbc.2021.100745},

issn = {1083-351X},

journal = {J Biol Chem},

volume = {296},

pages = {100745},

abstract = {Fifty years ago, the first landmark structures of antibodies heralded the dawn of structural immunology. Momentum then started to build toward understanding how antibodies could recognize the vast universe of potential antigens and how antibody-combining sites could be tailored to engage antigens with high specificity and affinity through recombination of germline genes (V, D, J) and somatic mutation. Equivalent groundbreaking structures in the cellular immune system appeared some 15 to 20 years later and illustrated how processed protein antigens in the form of peptides are presented by MHC molecules to T cell receptors. Structures of antigen receptors in the innate immune system then explained their inherent specificity for particular microbial antigens including lipids, carbohydrates, nucleic acids, small molecules, and specific proteins. These two sides of the immune system act immediately (innate) to particular microbial antigens or evolve (adaptive) to attain high specificity and affinity to a much wider range of antigens. We also include examples of other key receptors in the immune system (cytokine receptors) that regulate immunity and inflammation. Furthermore, these antigen receptors use a limited set of protein folds to accomplish their various immunological roles. The other main players are the antigens themselves. We focus on surface glycoproteins in enveloped viruses including SARS-CoV-2 that enable entry and egress into host cells and are targets for the antibody response. This review covers what we have learned over the past half century about the structural basis of the immune response to microbial pathogens and how that information can be utilized to design vaccines and therapeutics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}