1pgx
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THE 1.66 ANGSTROMS X-RAY STRUCTURE OF THE B2 IMMUNOGLOBULIN-BINDING DOMAIN OF STREPTOCOCCAL PROTEIN G AND COMPARISON TO THE NMR STRUCTURE OF THE B1 DOMAIN
OverviewOverview
The structure of the B2 immunoglobulin-binding domain of streptococcal, protein G has been determined at 1.67-A resolution using a combination of, single isomorphous replacement (SIR) phasing and manual fitting of the, coordinates of the NMR structure of B1 domain of streptococcal protein G, [Gronenborn, A. M., et al. (1991) Science 253, 657-661]. The final R value, was 0.191 for data between 8.0 and 1.67 A. The structure described here, has 13 residues preceding the 57-residue Ig-binding domain and 13, additional residues following it, for a total of 83 residues. The, 57-residue binding domain is well-determined in the structure, having an, average B factor of 18.0. Only residues 8-77 could be located in the, electron density maps, with the ends of the structure fading into, disorder. Like the B1 domain, the B2 domain consists of four beta-strands, and a single helix lying diagonally across the beta-sheet, with a -1, +3, chi, -1 topology. This small structure is extensively hydrogen-bonded and, has a relatively large hydrophobic core. These structural observations may, account for the exceptional stability of protein G. A comparison of the B2, domain X-ray structure and the B1 domain NMR structure showed minor, differences in the turn between strands and two and a slight displacement, of the helix relative to the sheet. Hydrogen bonds between, crystallographically related molecules account for most of these, differences.
About this StructureAbout this Structure
1PGX is a Single protein structure of sequence from Streptococcaceae. Full crystallographic information is available from OCA.
ReferenceReference
1.67-A X-ray structure of the B2 immunoglobulin-binding domain of streptococcal protein G and comparison to the NMR structure of the B1 domain., Achari A, Hale SP, Howard AJ, Clore GM, Gronenborn AM, Hardman KD, Whitlow M, Biochemistry. 1992 Nov 3;31(43):10449-57. PMID:1420164
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