Structure of coenzyme A-disulfide reductase from Staphylococcus aureus at 1.54 Å resolution
Structure of coenzyme A-disulfide reductase from Staphylococcus aureus at 1.54 Å resolution
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DOI：
10.1021/bi061139a
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发表时间：
2006-09-26
期刊：
影响因子：
2.9
通讯作者：
Claiborne, Al
中科院分区：
文献类型：
--
作者：
Mallett, T. Conn;Wallen, Jamie R.;Claiborne, Al
辅酶A（CoASH）取代谷胱甘肽作为金黄色葡萄球菌中的主要低分子量硫醇;它通过辅酶A-二硫键还原酶（CoADR）维持在还原状态，CoADR是一种类似于NADH过氧化物酶但含有新型Cys 43-SSCoA氧化还原中心的同二聚体酶。对S. aureus CoADR已使用多波长反常色散数据求解，并以1.54埃的分辨率进行了改进。得到的电子密度图定义了Cys 43-SSCoA二硫键构象，其中Cys 43-S-γ位于黄素si面，距离FAD-C4 aF 3.2埃，并且CoAS部分位于二聚体界面处的裂缝内的延伸构象中。有序的氯离子位于Cys 43-SSCoA二硫化物附近，并从互补亚基的Tyr 361 '-OH接收氢键，表明Tyr 361'在CoAS-二硫化物还原过程中作为酸碱催化剂的作用。Tyr 419 'OH也位于距离Tyr 361'-OH 3.2埃处，并且基于其在已知功能性CoADR中的保守性，似乎对活性也很重要。鉴定参与识别CoAS-二硫化物底物以及Cys 43-SSCoA氧化还原中心形成和稳定的残基，允许开发CoAS结合基序。生物信息学分析表明，CoADR酶广泛分布在细菌和古细菌王国，这表明在原核巯基/二硫化物稳态的CoASH/CoAS-二硫化物氧化还原系统的意义更广泛。
Coenzyme A (CoASH) replaces glutathione as the major low molecular weight thiol in Staphylococcus aureus; it is maintained in the reduced state by coenzyme A-disulfide reductase (CoADR), a homodimeric enzyme similar to NADH peroxidase but containing a novel Cys43-SSCoA redox center. The crystal structure of S. aureus CoADR has been solved using multiwavelength anomalous dispersion data and refined at a resolution of 1.54 angstrom. The resulting electron density maps define the Cys43-SSCoA disulfide conformation, with Cys43-S-gamma located at the flavin si face, 3.2 angstrom from FAD-C4aF, and the CoAS-moiety lying in an extended conformation within a cleft at the dimer interface. A well-ordered chloride ion is positioned adjacent to the Cys43-SSCoA disulfide and receives a hydrogen bond from Tyr361'-OH of the complementary subunit, suggesting a role for Tyr361' as an acid-base catalyst during the reduction of CoAS-disulfide. Tyr419'OH is located 3.2 angstrom from Tyr361'-OH as well and, based on its conservation in known functional CoADRs, also appears to be important for activity. Identification of residues involved in recognition of the CoAS-disulfide substrate and in formation and stabilization of the Cys43-SSCoA redox center has allowed development of a CoAS-binding motif. Bioinformatics analyses indicate that CoADR enzymes are broadly distributed in both bacterial and archaeal kingdoms, suggesting an even broader significance for the CoASH/CoAS-disulfide redox system in prokaryotic thiol/disulfide homeostasis.