Unraveling Cholesterol Catabolism in Mycobacterium tuberculosis: ChsE4-ChsE5 α(2)β(2) Acyl-CoA Dehydrogenase Initiates β-Oxidation of 3-Oxo-cholest-4-en-26-oyl CoA.
Unraveling Cholesterol Catabolism in Mycobacterium tuberculosis: ChsE4-ChsE5 α(2)β(2) Acyl-CoA Dehydrogenase Initiates β-Oxidation of 3-Oxo-cholest-4-en-26-oyl CoA.
复制标题
DOI：
10.1021/id500033m
复制
发表时间：
2015-02-13
影响因子：
5.3
通讯作者：
Sampson, Nicole S.
中科院分区：
文献类型：
--
作者：
Yang, Meng;Lu, Rui;Guja, Kip E.;Wipperman, Matthew F.;St Clair, Johnna R.;Bonds, Amber C.;Garcia-Diaz, Miguel;Sampson, Nicole S.
关键词：
结核分枝杆菌（Mtb）对宿主胆固醇的代谢是其毒力和发病机制的一个重要因素，尽管人们还不完全清楚胆固醇代谢是如何以及为什么需要的。Mtb使用一组独特的分解代谢酶，这些酶与脂肪酸经典β-氧化所需的酶同源，但对类固醇衍生底物具有特异性。在这里，我们确定并分配了其中两种酶的底物特异性，ChsE4-ChsE5 （Rv3504-Rv3505）和ChsE3 (Rv3573c)，它们在Mtb中进行胆固醇侧链氧化。稳态实验表明，ChsE4-ChsE5在胆固醇侧链β-氧化的第一个循环中优先催化3-氧-胆-4-烯-26-油基辅酶a的氧化，最终生成丙酰辅酶a，而ChsE3在β-氧化的第二个循环中特异性催化3-氧-胆-4-烯-24-油基辅酶a的氧化，生成乙酰-辅酶a。而ChsE4-ChsE5可以催化3-氧-胆-4-烯-24-油基辅酶a和3-氧-4-孕烯-20-羧基辅酶a的氧化。ChsE4-ChsE5的功能冗余解释了结核分枝杆菌igr敲除菌株的体内表型；在慢性感染阶段，ChsE1-ChsE2的缺失可以通过ChsE4-ChsE5来弥补。ChsE4-ChsE5的x射线晶体结构分辨率为2.0 Å，是异四聚酰基辅酶a脱氢酶（ACAD）的第一个高分辨率结构。与典型的四聚体acad结合四个黄嘌呤二核苷酸（FAD）辅助因子不同，ChsE4-ChsE5在每个二聚体界面上结合一个FAD，导致只有两个底物结合位点，而不是传统的四个活性位点。通过将ChsE4-ChsE5底物结合位点与已知哺乳动物ACADs的结合位点进行比较，发现ChsE4-ChsE5底物结合腔扩大，可容纳类固醇底物，并强调了设计抑制结核分枝杆菌降解胆固醇侧链第一循环中β-氧化步骤的新前景。
The metabolism of host cholesterol by Mycobacterium tuberculosis (Mtb) is an important factor for both its virulence and pathogenesis, although how and why cholesterol metabolism is required is not fully understood. Mtb uses a unique set of catabolic enzymes that are homologous to those required for classical β-oxidation of fatty acids but are specific for steroid-derived substrates. Here, we identify and assign the substrate specificities of two of these enzymes, ChsE4-ChsE5 (Rv3504-Rv3505) and ChsE3 (Rv3573c), that carry out cholesterol side chain oxidation in Mtb. Steady-state assays demonstrate that ChsE4-ChsE5 preferentially catalyzes the oxidation of 3-oxo-cholest-4-en-26-oyl CoA in the first cycle of cholesterol side chain β-oxidation that ultimately yields propionyl-CoA, whereas ChsE3 specifically catalyzes the oxidation of 3-oxo-chol-4-en-24-oyl CoA in the second cycle of β-oxidation that generates acetyl-CoA. However, ChsE4-ChsE5 can catalyze the oxidation of 3-oxo-chol-4-en-24-oyl CoA as well as 3-oxo-4-pregnene-20-carboxyl-CoA. The functional redundancy of ChsE4-ChsE5 explains the in vivo phenotype of the igr knockout strain of Mycobacterium tuberculosis; the loss of ChsE1-ChsE2 can be compensated for by ChsE4-ChsE5 during the chronic phase of infection. The X-ray crystallographic structure of ChsE4-ChsE5 was determined to a resolution of 2.0 Å and represents the first high-resolution structure of a heterotetrameric acyl-CoA dehydrogenase (ACAD). Unlike typical homotetrameric ACADs that bind four flavin adenine dinucleotide (FAD) cofactors, ChsE4-ChsE5 binds one FAD at each dimer interface, resulting in only two substrate-binding sites rather than the classical four active sites. A comparison of the ChsE4-ChsE5 substrate-binding site to those of known mammalian ACADs reveals an enlarged binding cavity that accommodates steroid substrates and highlights novel prospects for designing inhibitors against the committed β-oxidation step in the first cycle of cholesterol side chain degradation by Mtb.
登录
查看更多内容
DOI：
10.1073/pnas.90.16.7523
发表时间：
1993-08-15
影响因子：
11.1
作者：
KIM, JJP;WANG, M;PASCHKE, R
通讯作者：
PASCHKE, R
DOI：
10.1107/s090744490200118x
发表时间：
2002-03-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Dauter, Z;Dauter, M;Dodson, E
通讯作者：
Dodson, E
影响因子：
2.5
作者：
Allaire, Marc;Yang, Lin
通讯作者：
Yang, Lin
影响因子：
5.8
作者：
Kozlikova, Barbora;Sebestova, Eva;Sochor, Jiri
通讯作者：
Sochor, Jiri
影响因子：
3.2
作者：
Chang, Jennifer C.;Miner, Maurine D.;Sherman, David R.
通讯作者：
Sherman, David R.