1s4g
From Proteopedia
Somatomedin-B Domain of human plasma vitronectin.
Overview
The three-dimensional structure of an N-terminal fragment comprising the first 51 amino acids from human plasma vitronectin, the somatomedin B (SMB) domain, has been determined by two-dimensional NMR approaches. An average structure was calculated, representing the overall fold from a set of 20 minimized structures. The core residues (18-41) overlay with a root mean square deviation of 2.29 +/- 0.62 A. The N- and C-terminal segments exhibit higher root mean square deviations, reflecting more flexibility in solution and/or fewer long-range NOEs for these regions. Residues 26-30 form a unique single-turn alpha-helix, the locus where plasminogen activator inhibitor type-1 (PAI-1) is bound. This structure of this helix is highly homologous with that of a recombinant SMB domain solved in a co-crystal with PAI-1 (Zhou, A., Huntington, J. A., Pannu, N. S., Carrell, R. W., and Read, R. J. (2003) Nat. Struct. Biol. 10, 541-544), although the remainder of the structure differs. Significantly, the pattern of disulfide cross-links observed in this material isolated from human plasma is altogether different from the disulfides proposed for recombinant forms. The NMR structure reveals the relative orientation of binding sites for cell surface receptors, including an integrin-binding site at residues 45-47, which was disordered and did not diffract in the co-crystal, and a site for the urokinase receptor, which overlaps with the PAI-1-binding site.
About this Structure
1S4G is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The solution structure of the N-terminal domain of human vitronectin: proximal sites that regulate fibrinolysis and cell migration., Mayasundari A, Whittemore NA, Serpersu EH, Peterson CB, J Biol Chem. 2004 Jul 9;279(28):29359-66. Epub 2004 Apr 30. PMID:15123712 Page seeded by OCA on Sat May 3 08:17:01 2008
