A tetrameric structure is not essential for activity in dihydrodipicolinate synthase (DHDPS) from Mycobacterium tuberculosis
A tetrameric structure is not essential for activity in dihydrodipicolinate synthase (DHDPS) from Mycobacterium tuberculosis
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DOI：
10.1016/j.abb.2011.05.014
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发表时间：
2011-08-15
影响因子：
3.9
通讯作者：
Gerrard, Juliet A.
中科院分区：
文献类型：
--
作者：
Evans, Genevieve;Schuldt, Linda;Gerrard, Juliet A.
二氢二吡啶合酶（DHDPS）是一种经过验证的抗生素靶点，提出了一种新的抑制剂设计方法：通过靶向二聚体-二聚体界面来破坏天然四聚体的形成。本研究通过合理设计，获得了结核分枝杆菌Mtb-DHDPS-A204R四元结构断裂的变异株。x射线晶体学（2.1埃分辨率）显示二聚体蛋白具有与四聚体野生型酶相同的折叠和活性位点结构。分析超离心证实了溶液中的二聚体结构，但二聚体突变体具有与野生型酶相似的活性。虽然对这两种底物的亲和力有所降低，但根据先前的结果，该酶的高催化能力令人惊讶，该结果表明，大肠杆菌和炭疽芽孢杆菌的二聚体变体DHDPS酶的活性与野生型四聚体相比显着降低。这些结果表明Mtb-DHDPS-A204R与来自金黄色葡萄球菌的天然二聚体酶相似，并突出了我们对寡聚化在相关蛋白质结构和功能中所起作用的不完整理解。(C) 2011爱思唯尔公司版权所有。
Dihydrodipicolinate synthase (DHDPS) is a validated antibiotic target for which a new approach to inhibitor design has been proposed: disrupting native tetramer formation by targeting the dimer-dimer interface. In this study, rational design afforded a variant of Mycobacterium tuberculosis, Mtb-DHDPS-A204R, with disrupted quaternary structure. X-ray crystallography (at a resolution of 2.1 angstrom) revealed a dimeric protein with an identical fold and active-site structure to the tetrameric wild-type enzyme. Analytical ultracentrifugation confirmed the dimeric structure in solution, yet the dimeric mutant has similar activity to the wild-type enzyme. Although the affinity for both substrates was somewhat decreased, the high catalytic competency of the enzyme was surprising in the light of previous results showing that dimeric variants of the Escherichia coli and Bacillus anthracis DHDPS enzymes have dramatically reduced activity compared to their wild-type tetrameric counterparts. These results suggest that Mtb-DHDPS-A204R is similar to the natively dimeric enzyme from Staphylococcus aureus, and highlight our incomplete understanding of the role played by oligomerisation in relating protein structure and function. (C) 2011 Elsevier Inc. All rights reserved.