1gab
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STRUCTURE OF AN ALBUMIN-BINDING DOMAIN, NMR, 20 STRUCTURES
OverviewOverview
The albumin-binding GA module is found in a family of surface proteins of, different bacterial species. It comprises 45 amino acid residues and, represents the first known example of contemporary module shuffling. Using, 1H NMR spectroscopy we have determined the solution structure of the GA, module from protein PAB, a protein of the anaerobic human commensal and, pathogen Peptostreptococcus magnus. This structure, the first, three-dimensional structure of an albumin-binding protein domain, described, was shown to be composed of a left-handed three-helix-bundle., Sequence differences between GA modules with different affinities for, albumin indicated that a conserved region in the C-terminal part of the, second helix and the flexible sequence between helices 2 and 3 could, contribute to the albumin-binding activity. The effect on backbone amide, proton exchange rates upon binding to albumin support this assumption. The, GA module has a fold that is strikingly similar to the, immunoglobulin-binding domains of staphylococcal protein A but it shows no, resemblance to the fold shared by the immunoglobulin-binding domains of, streptococcal protein G and peptostreptococcal protein L. When the gene, sequences, binding properties and thermal stability of these four domains, are analysed in relation to their global folds an evolutionary pattern, emerges. Thus, in the evolution of novel binding properties mutations are, allowed only as long as the energetically favourable global fold is, maintained.
About this StructureAbout this Structure
1GAB is a Single protein structure of sequence from Finegoldia magna. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure of the albumin-binding GA module: a versatile bacterial protein domain., Johansson MU, de Chateau M, Wikstrom M, Forsen S, Drakenberg T, Bjorck L, J Mol Biol. 1997 Mar 14;266(5):859-65. PMID:9086265
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