2ou1: Difference between revisions

[[Image:2ou1.gif|left|200px]]<br /><applet load="2ou1" size="350" color="white" frame="true" align="right" spinBox="true"  

Apolipoproteins 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.

2OU1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry 1L6K. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OU1 OCA].  

[[Category: Carson, M C.]]

[[Category: Hussain, M M.]]

[[Category: Kumar, M S.]]

[[Category: Murthy, H M.K.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:22:27 2008''