进化烯醇酶酶活性的总科:o-succinylbenzoate合成酶的结构从大肠杆菌与Mg2 +和o-succinylbenzoate复杂。
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汤普森结核病,Garrett JB,泰勒EA Meganathan R, Gerlt JA, Rayment我
进化烯醇酶酶活性的总科:o-succinylbenzoate合成酶的结构从大肠杆菌与Mg2 +和o-succinylbenzoate复杂。
生物化学。2000年9月5日,39 (35):10662 - 76。
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10978150 (在PubMed]
- 文摘
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配体的x射线结构自由(apo)和镁(2 +)* o-succinylbenzoate (OSB)产品复杂o-succinylbenzoate合成酶(OSB)大肠杆菌已经解决了1.65和1.77分辨率,分别。apo的osb的结构是由多个同形替代解决空间群P2 (1) 2 (1) 2 (1);复杂的结构与镁(2 +)*的OSB解决分子置换空间群P2 (1) 2 (1) 2。发现的两个域褶皱的osb是类似发现烯醇酶家族的其他成员:混合α/β限制域由段在N - c终端的多肽和更大(β/α)(7)β桶域。两个地区的疾病被发现的osb朊的结构:(i)前两个之间的循环beta-strandsα/β域;和(2)中的第一个sheet-helix两桶域。这些区域被命令在产品与镁(2 +)*的OSB复杂。正如所料,镁(2 +)* OSB一对必然年底c端桶域。的电子密度苯基琥珀酸产品的组件是明确的;然而,1-carboxylate似乎采取多种构象。 The metal is octahedrally coordinated by Asp(161), Glu(190), and Asp(213), two water molecules, and one oxygen of the benzoate carboxylate group of OSB. The loop between the first two beta-strands in the alpha/beta motif interacts with the aromatic ring of OSB. Lys(133) and Lys(235) are positioned to function as acid/base catalysts in the dehydration reaction. Few hydrogen bonding or electrostatic interactions are involved in the binding of OSB to the active site; instead, most of the interactions between OSB and the protein are either indirect via water molecules or via hydrophobic interactions. As a result, evolution of both the shape and the volume of the active site should be subject to few structural constraints. This would provide a structural strategy for the evolution of new catalytic activities in homologues of OSBS and a likely explanation for how the OSBS from Amycolaptosis also can catalyze the racemization of N-acylamino acids [Palmer, D. R., Garrett, J. B., Sharma, V., Meganathan, R., Babbitt, P. C., and Gerlt, J. A. (1999) Biochemistry 38, 4252-4258].