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NMR STRUCTURE OF AN EXCHANGEABLE APOLIPOPROTEIN-MANDUCA SEXTA APOLIPOPHORIN-IIINMR STRUCTURE OF AN EXCHANGEABLE APOLIPOPROTEIN-MANDUCA SEXTA APOLIPOPHORIN-III
Structural highlights
Function[APL3_MANSE] Assists in the loading of diacylglycerol, generated from triacylglycerol stores in the fat body through the action of adipokinetic hormone, into lipophorin, the hemolymph lipoprotein. It increases the lipid carrying capacity of lipophorin by covering the expanding hydrophobic surface resulting from diacylglycerol uptake. It thus plays a critical role in the transport of lipids during flight in several species of insects. Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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