Enzymatic β-Oxidation of the Cholesterol Side Chain in Mycobacterium tuberculosis Bifurcates Stereospecifically at Hydration of 3-Oxo-cholest-4,22-dien-24-oyl-CoA.
Enzymatic β-Oxidation of the Cholesterol Side Chain in Mycobacterium tuberculosis Bifurcates Stereospecifically at Hydration of 3-Oxo-cholest-4,22-dien-24-oyl-CoA.
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DOI：
10.1021/acsinfecdis.1c00069
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发表时间：
2021-06-11
影响因子：
5.3
通讯作者：
Sampson NS
中科院分区：
文献类型：
--
作者：
Yuan T;Werman JM;Yin X;Yang M;Garcia-Diaz M;Sampson NS
结核分枝杆菌（Mtb）利用宿主脂质（如胆固醇）维持生存、持久和毒力的独特能力，使胆固醇的代谢途径成为治疗开发的一个非常感兴趣的领域。在此，我们从结核分枝杆菌基因组cho区（负责胆固醇分解代谢的基因组位点）中鉴定并表征了chsH3 （Rv3538）和chsB1 （Rv3502c）两个基因。它们的蛋白质产物在胆固醇侧链的β-氧化中催化两个连续的立体特异性水合和脱氢步骤。ChsH3有利于3-氧-胆碱-4,22-二烯-24-酰基辅酶a的22S水化，而之前报道的EchA19 （Rv3516）则可以催化相同的烯-辅酶a底物生成(22R)-羟基-3-氧-胆碱-4-烯-24-酰基辅酶a。ChsB1具有立体特异性，能催化ChsH3产物脱氢，但不能催化EchA19产物脱氢。ChsB1载脂蛋白的x射线晶体结构以2.03 Å的分辨率测定，结合NAD+辅因子的全酶以2.21 Å的分辨率测定。同型二聚体结构是典型的NAD+利用短链型醇脱氢酶/还原酶的代表，包括一个罗斯曼折叠基元，但表现出独特的底物结合位点结构，其长度和宽度比其同源对应物更大，可能容纳庞大的类固醇底物。有趣的是，Mtb在甾醇侧链分解代谢中利用maoc样家族的水合酶，而在其他物种中利用进化上独特的crotonase家族的水合酶进行脂肪酸β氧化。
The unique ability of Mycobacterium tuberculosis (Mtb) to utilize host lipids such as cholesterol for survival, persistence, and virulence has made the metabolic pathway of cholesterol an area of great interest for therapeutics development. Herein, we identify and characterize two genes from the Cho-region (genomic locus responsible for cholesterol catabolism) of the Mtb genome, chsH3 (Rv3538) and chsB1 (Rv3502c). Their protein products catalyze two sequential stereospecific hydration and dehydrogenation steps in the β-oxidation of the cholesterol side chain. ChsH3 favors the 22S hydration of 3-oxo-cholest-4,22-dien-24-oyl-CoA in contrast to the previously reported EchA19 (Rv3516), which catalyzes formation of the (22R)-hydroxy-3-oxo-cholest-4-en-24-oyl-CoA from the same enoyl-CoA substrate. ChsB1 is stereospecific and catalyzes dehydrogenation of the ChsH3 product but not the EchA19 product. The X-ray crystallographic structure of the ChsB1 apo-protein was determined at a resolution of 2.03 Å, and the holo-enzyme with bound NAD+ cofactor was determined at a resolution of 2.21 Å. The homodimeric structure is representative of a classical NAD+-utilizing short-chain type alcohol dehydrogenase/reductase, including a Rossmann-fold motif, but exhibits a unique substrate binding site architecture that is of greater length and width than its homologous counterparts, likely to accommodate the bulky steroid substrate. Intriguingly, Mtb utilizes hydratases from the MaoC-like family in sterol side-chain catabolism in contrast to fatty acid β-oxidation in other species that utilize the evolutionarily distinct crotonase family of hydratases.
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影响因子：
5.8
作者：
Stivala, Alex;Wybrow, Michael;Stuckey, Peter J.
通讯作者：
Stuckey, Peter J.
影响因子：
--
作者：
de Carvalho, Luiz Pedro S.;Fischer, Steven M.;Rhee, Kyu Y.
通讯作者：
Rhee, Kyu Y.
影响因子：
4.4
作者：
Holert, Johannes;Brown, Kirstin;Mohna, William W.
通讯作者：
Mohna, William W.
结核分枝杆菌利用独特的杂元结构来脱氢侧链。
影响因子：
2.9
作者：
Thomas, Suzanne T.;Sampson, Nicole S.
通讯作者：
Sampson, Nicole S.
影响因子：
5.7
作者：
Schaefer, Christin M.;Lu, Rui;Nesbitt, Natasha M.;Schiebel, Johannes;Sampson, Nicole S.;Kisker, Caroline
通讯作者：
Kisker, Caroline