1u2h
From Proteopedia
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X-ray Structure of the N-terminally truncated human APEP-1
Overview
BACKGROUND: Human Aortic Preferentially Expressed Protein-1 (APEG-1) is a, novel specific smooth muscle differentiation marker thought to play a role, in the growth and differentiation of arterial smooth muscle cells (SMCs)., RESULTS: Good quality crystals that were suitable for X-ray, crystallographic studies were obtained following the truncation of the 14, N-terminal amino acids of APEG-1, a region predicted to be disordered. The, truncated protein (termed DeltaAPEG-1) consists of a single immunoglobulin, (Ig) like domain which includes an Arg-Gly-Asp (RGD) adhesion recognition, motif. The RGD motif is crucial for the interaction of extracellular, proteins and plays a role in cell adhesion. The X-ray structure of, DeltaAPEG-1 was determined and was refined to sub-atomic resolution (0.96, A). This is the best resolution for an immunoglobulin domain structure so, far. The structure adopts a Greek-key beta-sandwich fold and belongs to, the I (intermediate) set of the immunoglobulin superfamily. The residues, lying between the beta-sheets form a hydrophobic core. The RGD motif folds, into a 310 helix that is involved in the formation of a homodimer in the, crystal which is mainly stabilized by salt bridges. Analytical, ultracentrifugation studies revealed a moderate dissociation constant of, 20 microM at physiological ionic strength, suggesting that APEG-1, dimerisation is only transient in the cell. The binding constant is, strongly dependent on ionic strength. CONCLUSION: Our data suggests that, the RGD motif might play a role not only in the adhesion of extracellular, proteins but also in intracellular protein-protein interactions. However, it remains to be established whether the rather weak dimerisation of, APEG-1 involving this motif is physiologically relevant.
About this Structure
1U2H is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
X-ray structure of engineered human Aortic Preferentially Expressed Protein-1 (APEG-1)., Manjasetty BA, Niesen FH, Scheich C, Roske Y, Goetz F, Behlke J, Sievert V, Heinemann U, Bussow K, BMC Struct Biol. 2005 Dec 14;5:21. PMID:16354304
Page seeded by OCA on Mon Nov 12 19:30:35 2007
