Structural highlights
Function[APOA2_HUMAN] May stabilize HDL (high density lipoprotein) structure by its association with lipids, and affect the HDL metabolism. 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 PubMedApolipoproteins A-I and A-II form the major protein constituents of high-density lipid particles (HDL), the concentration of which is inversely correlated with the frequency of heart disease in humans. Although the physiological role of apolipoprotein A-II is unclear, evidence for its involvement in free fatty acid metabolism in mice has recently been obtained. Currently, the best characterized activity of apolipoprotein A-II is its potent antagonism of the anti-atherogenic and anti-inflammatory activities of apolipoprotein A-I, probably due to its competition with the latter for lipid acyl side chains in HDL. Many interactions of apolipoprotein A-I with enzymes and proteins involved in reverse cholesterol transport and HDL maturation are mediated by lipid-bound protein. The structural bases of interaction with lipids are expected to be common to exchangeable apolipoproteins and attributable to amphipathic alpha-helices present in each of them. Thus, characterization of apolipoprotein-lipid interactions in any apolipoprotein is likely to provide information that is applicable to the entire class. We report structures of human apolipoprotein A-II and its complex with beta-octyl glucoside, a widely used lipid surrogate. The former shows that disulfide-linked dimers of apolipoprotein A-II form amphipathic alpha-helices which aggregate into tetramers. Dramatic changes, observed in the presence of beta-octyl glucoside, might provide clues to the structural basis for its antagonism of apolipoprotein A-I. Additionally, excursions of individual molecules of apolipoprotein A-II from a common helical architecture in both structures indicate that lipid-bound apolipoproteins are likely to have an ensemble of related conformations. These structures provide the first experimental paradigm for description of apolipoprotein-lipid interactions at the atomic level. Structures of apolipoprotein A-II and a lipid-surrogate complex provide insights into apolipoprotein-lipid interactions.,Kumar MS, Carson M, Hussain MM, Murthy HM Biochemistry. 2002 Oct 1;41(39):11681-91. PMID:12269810[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||
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