Prostaglandin F2α formation from prostaglandin H2 by prostaglandin F synthase (PGFS):: Crystal structure of PGFS containing bimatoprost
Prostaglandin F2α formation from prostaglandin H2 by prostaglandin F synthase (PGFS):: Crystal structure of PGFS containing bimatoprost
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DOI：
10.1021/bi051861t
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发表时间：
2006-02-21
期刊：
影响因子：
2.9
通讯作者：
Takusagawa, F
中科院分区：
文献类型：
--
作者：
Komoto, J;Yamada, T;Takusagawa, F
由花生四烯酸形成的前列腺素H-2（PGH（2））是一种不稳定的中间体，在酶的作用下有效地转化为更稳定的花生四烯酸代谢产物。前列腺素F合酶（PGFS）具有双重催化活性：在NADPH存在下，通过PGH（2）的9，11-内过氧化物还原酶活性从PGH（2）形成PGF（2 α），以及通过PGD 2的11-酮还原酶活性从PGD（2）形成9 α，11 β-PGF（2）（PGF（2 α β））。比马前列素（BMP）是一种高效的眼部消肿剂，是一种PGF（2 α）类似物，可抑制PGFS的PGD 2 11-酮还原酶和PGH 2 9，11-内过氧化物还原酶活性。为了研究PGH 2 9，11-内过氧化物还原酶的催化机制，已在2.0埃分辨率下测定了PGFs[NADPH + BMP]的晶体结构。BMP在PGD（2）结合位点附近结合，但BMP的α链和ω链分别位于PGD（2）的ω链和α链上。因此，结合的BMP和PGD 2将它们的环戊烷部分的相对面导向结合的NADP的烟酰胺环。BMP的α-和ω-链参与与蛋白质残基的H-键合，而环戊烷部分被水分子包围，并且不直接连接到蛋白质或结合的NADPH，表明环戊烷部分在活性位点中是可移动的。从复杂结构出发，建立了含有PGF（2 α）和PGH（2）的PGFS的两种模型结构。根据模型结构和抑制数据，提出了PGFS的PGH（2）9，11-内过氧化物还原酶的催化机理。由PGH（2）形成PGF（2 α）最可能涉及从结合的NADPH到PGH（2）的内过氧化物的直接氢化物转移，而没有特定氨基酸残基的参与。
Prostaglandin H-2 (PGH(2)) formed from arachidonic acid is an unstable intermediate and is efficiently converted into more stable arachidonate metabolites by the action of enzymes. Prostaglandin F synthase (PGFS) has dual catalytic activities: formation of PGF(2 alpha) from PGH(2) by the PGH(2) 9,11-endoperoxide reductase activity and 9 alpha,11 beta-PGF(2) (PGF(2 alpha beta)) from PGD(2) by the PGD2 11-ketoreductase activity in the presence of NADPH. Bimatoprost (BMP), which is a highly effective ocular hypotensive agent, is a PGF(2 alpha) analogue that inhibits both the PGD2 11-ketoreductase and PGH2 9,11-endoperoxide reductase activities of PGFS. To examine the catalytic mechanism of PGH2 9,11-endoperoxide reductase, a crystal structure of PGFS[NADPH + BMP] has been determined at 2.0 angstrom resolution. BMP binds near the PGD(2) binding site, but the alpha- and omega-chains of BMP are locate on the omega- and alpha-chains of PGD(2), respectively. Consequently, the bound BMP and PGD2 direct their opposite faces of the cyclopentane moieties toward the nicotinamide ring of the bound NADP. The alpha- and omega-chains of BMP are involved in H-bonding with protein residues, while the cyclopentane moiety is surrounded by water molecules and is not directly attached to either the protein or the bound NADPH, indicating that the cyclopentane moiety is movable in the active site. From the complex structure, two model structures of PGFS containing PGF(2 alpha) and PGH(2) were built. On the basis of the model structures and inhibition data, a putative catalytic mechanism of PGH(2) 9,11-endoperoxide reductase of PGFS is proposed. Formation of PGF(2 alpha) from PGH(2) most likely involves a direct hydride transfer from the bound NADPH to the endoperoxide of PGH(2) without the participation of specific amino acid residues.