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PubMed1999

Methods for X-ray diffraction analysis of macromolecular structures.

A modern approach to protein crystallography relies as much on molecular biology as on the 'core' crystallographic disciplines. Some recent, biologically significant structure determinations have demonstrated this and show the importance of new third generation synchrotron sources. Novel uses of well known phasing techniques have also been valuable in these structure determinations. For the majority of structures, advances in phasing techniques, data collection and processing and the associated computer programs have led to more effective structure determinations.

Animals↗

PubMed1997

Structure of the Fab fragment from a neutralizing monoclonal antibody directed against an epitope of gp41 from HIV-1.

The structure of a Fab fragment of a monoclonal antibody (1583) that neutralizes a broad range of HIV-1 isolates has been solved by X-ray crystallography. This antibody is directed against a poliovirus/HIV-I chimaera which presents a conserved epitope of the envelope protein gp41. Crystals of 1583 were obtained in the space group P2(1)2(1)2(1) and the structure solved by molecular replacement. The model has been refined against all data in the range 10-2.9 A to a final crystallographic R factor of 0.198. The antigen-binding site features a well defined groove, typical of antibodies that bind to small antigens, created in part by a relatively short CDR H3. The variable regions of 1583 were sequenced and, given the hydrophilic nature of the epitope, revealed a surprising lack of charged residues in the CDR's. However, the antigen-binding cleft is indeed very polar, due in part to the presence of two charged residues that emanate from outside the recognized CDR's.

Journal Article↗