Crystallographic structure of a peptidyl keto acid inhibitor and human alpha-thrombin.
Crystallographic structure of a peptidyl keto acid inhibitor and human alpha-thrombin.
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肽基酮酸抑制剂和人α-凝血酶的晶体结构。
DOI：
10.1016/0968-0896(95)00096-y
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发表时间：
1995
影响因子：
3.5
通讯作者：
Brunck,TK
中科院分区：
文献类型：
--
作者：
Håkansson,K;Tulinsky,A;Abelman,MM;Miller,TA;Vlasuk,GP;Bergum,PW;Lim-Wilby,MS;Brunck,TK
Benzyl-SO2-Met(O2)-Pro-Arg(CO)((CONH)CH2)-ph4enyl，是一种低分子量的α-酮酰胺抑制剂，是一种缓慢的紧结合的α-凝血酶氨解活性的抑制剂，其Ki=1.2 8×10−10M。用结晶学方法测定并精制了人α-凝血酶与CVS1347的水解物之间的络合物。晶体属单斜晶系C2，晶胞尺寸a=71.08A，b=72.05A，c=72.98Å，β=100.8°。用同晶代换方法求解了该结构，并对其进行了改进，分辨率范围为(8.00-1.76)ä，R值为0.162。正如Pro-Arg凝血酶抑制剂通常观察到的那样，抑制物的Pro-Arg核心分别结合在S2和S1亚基上。Met(O2)侧链不与酶紧密接触，但影响Glu192的构象；N-末端的苯磺酰基与活性中心疏水部分的Trp215发生芳香-芳香接触。蛋白降解抑制剂的α-酮羧酸与氧阴离子空穴中的羧酸基结合，表明该区域可以容纳蛋白酶-多肽复合体中的阴离子。α-酮基与活性中心中两个最重要的残基相互作用密切：碳原子在活性中心Ser195 Oγ的共价键距离内，羰基氧与His57氢键。因此，这些残基在催化中起到路易斯酸和碱的作用，相对于底物的剪切键的羰基碳和肽氮原子。
The low molecular weight α-keto amide inhibitor CVS-1347, benzyl-SO2-Met(O2)-Pro-Arg(CO)((CONH)CH2)-ph4enyl, is a slow, tight binding inhibitor of α-thrombin amidolytic activity having a Ki= 1.28 × 10−10M. A complex between human α-thrombin and a hydrolysis product of CVS-1347 has been determined and refined using crystallography. The crystals belong to monoclinic space group C2 with cell dimensions of a = 71.08, b = 72.05 and c = 72.98 A ̊ and β = 100.8° . The structure was solved using isomorphous replacement methods and refined with resolution limits of (8.00–1.76) Å to an R-value of 0.162. The Pro-Arg core of the inhibitor binds in the S2 and S1 subsites respectively, as is usually observed for Pro-Arg thrombin inhibitors. The Met(O2) side chain does not make any close contacts with the enzyme but influences the conformation of Glu192; the N-terminal benzylsulfonyl group makes an aromatic-aromatic contact with Trp215 in the hydrophobic part of the active site. The α-keto carboxylic acid of the proteolyzed inhibitor binds with the carboxylate group in the oxyanion hole, demonstrating that this region can accommodate an anion in a protease-peptide complex. The α-keto carbonyl group interacts closely with the two most important residues in the active site: the carbon atom is within a covalent bond distance of the active site Ser195 Oγ and the carbonyl oxygen is hydrogen bonded to His57. These residues thus act as a Lewis acid and base in catalysis with respect to the substrate carbonyl carbon and peptide nitrogen atoms of the scissile bond of substrate.