1eq1
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NMR STRUCTURE OF AN EXCHANGEABLE APOLIPOPROTEIN-MANDUCA SEXTA APOLIPOPHORIN-III
OverviewOverview
The high-resolution NMR structure of apolipophorin III from the sphinx moth, Manduca sexta, has been determined in the lipid-free state. We show that lipid-free apolipophorin III adopts a unique helix-bundle topology that has several characteristic structural features. These include a marginally stable, up-and-down helix bundle that allows for concerted opening of the bundle about "hinged" loops upon lipid interaction and buried polar/ionizable residues and buried interhelical H-bonds located in the otherwise hydrophobic interior of the bundle that adjust protein stability and facilitate lipid-induced conformational opening. We suggest that these structural features modulate the conformational adaptability of the lipid-free helix bundle upon lipid binding and control return of the open conformation to the original lipid-free helix-bundle state. Taken together, these data provide a structural rationale for the ability of exchangeable apolipoproteins to reversibly interact with circulating lipoprotein particles.
About this StructureAbout this Structure
1EQ1 is a Single protein structure of sequence from Manduca sexta. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for the conformational adaptability of apolipophorin III, a helix-bundle exchangeable apolipoprotein., Wang J, Sykes BD, Ryan RO, Proc Natl Acad Sci U S A. 2002 Feb 5;99(3):1188-93. Epub 2002 Jan 29. PMID:11818551
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