复杂结构的恶性疟原虫triosephosphate isomerase-phosphoglycolate两个晶体形式:表征配体的催化循环开放和封闭构象状态。
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从事年代,Ravindra G,巴拉罗姆H,巴拉罗姆P,没吃
复杂结构的恶性疟原虫triosephosphate isomerase-phosphoglycolate两个晶体形式:表征配体的催化循环开放和封闭构象状态。
生物化学。2002年11月5日,41 (44):13178 - 88。
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12403619 (在PubMed]
- 文摘
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Triosephosphate异构酶(TIM)已经被许多结构和机械的研究的主题。在96的位置,有一个高度保守的Ser残渣,近端催化部位。到目前为止,没有特定的角色赋予这个残渣。恶性疟原虫蒂姆(PfTIM),一个完整的酶催化地活跃,独特之处在于拥有一个板式换热器残留在96位置。PfTIM的结构复杂,phosphoglycolate (PG),决定了过渡态类似物,为了调查突变的影响在96年剩余的本质inhibitor-enzyme交互和关键的催化循环的方向(166 - 176)循环6,残留在蒂姆。晶体结构的phosphoglycolate PfTIM多元斜方晶系的(P2(1) 2(1) 2(1))和单斜(C2)形式的决议确定和细化2.8和1.9,分别。P2(1) 2(1) 2(1)形式包含两个二聚体的不对称单元。C2表格,分子和晶体2倍轴是重合的,导致单体的不对称单元。催化循环采用开放状态P2(1) 2(1) 2(1)形式和封闭在C2晶体构象。循环的开放构型的P2(1) 2(1) 2(1)形式似乎是板式换热器突变的Ser残留的结果96。 The steric clash between Phe96 and Ile172 probably impedes loop closure in PfTIM-ligand complexes. The PfTIM-PG complex is the first example of a TIM-ligand complex being observed in both loop open and closed forms. In the C2 form (loop closed), Phe96 and Leu167 adopt alternative conformations that are different from the ones observed in the open form, permitting loop closure. These structures provide strong support for the view that loop closure is not essential for ligand binding and that dynamic loop movement may occur in both free and ligand-bound forms of the enzyme.