Crystal structure of dimethyl sulfoxide reductase from Rhodobacter capsulatus at 1.88 A resolution.
Crystal structure of dimethyl sulfoxide reductase from Rhodobacter capsulatus at 1.88 A resolution.
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荚膜红杆菌二甲亚砜还原酶的晶体结构，分辨率为 1.88 A。
DOI：
10.1006/jmbi.1996.0555
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发表时间：
1996
影响因子：
5.6
通讯作者：
Knäblein,J
中科院分区：
文献类型：
--
作者：
Schneider,F;Löwe,J;Huber,R;Schindelin,H;Kisker,C;Knäblein,J
光合紫色细菌Rhodobacter capsulatus的周质二甲基亚砜还原酶（DMSOR）是呼吸链的末端电子受体。该酶催化高度氧化的底物如二甲亚砜还原为二甲硫醚。在钼氧化还原中心，两个单电子从细胞色素556转移到底物二甲亚砜，产生二甲基硫醚和（两个质子）水。该酶经纯化和结晶，空间群为P41212，晶胞尺寸为a =B=80.7 nm，c =229.2 nm。这种晶体在同步辐射下的辐射能超过1.8欧姆。三维结构的求解是通过多个同晶置换和分子置换技术相结合。对于57，394个独立反射，原子模型被细化到0.169的R因子。球形蛋白质由四个结构域组成，具有漏斗状空腔，导致可自由进入的金属离子氧化还原中心。单链蛋白质（85，033 Da）的双（异蝶呤鸟嘌呤二核苷酸）钼辅因子（1541 Da）具有与仅一个异蝶呤鸟嘌呤二核苷酸分子的顺式二硫烯基团结合的钼离子。三个额外的配体，两个氧代基团和丝氨酸侧链的氧，结合到钼离子。第二个异色蝶呤系统不是金属中心的配体球的一部分，其硫原子距离为3.5和3.8 μ m。它可能参与电子从蛋白质表面到钼中心的穿梭。
The periplasmic dimethyl sulfoxide reductase (DMSOR) from the photosynthetic purple bacteriumRhodobacter capsulatusfunctions as the terminal electron acceptor in its respiratory chain. The enzyme catalyzes the reduction of highly oxidized substrates like dimethyl sulfoxide to dimethyl sulfide. At a molybdenum redox center, two single electrons are transferred from cytochromec556to the substrate dimethyl sulfoxide, generating dimethyl sulfide and (with two protons) water. The enzyme was purified and crystallized in space groupP41212 with unit cell dimensions ofa=b=80.7 Å andc=229.2 Å. The crystals diffract beyond 1.8 Å with synchrotron radiation. The three-dimensional structure was solved by a combination of multiple isomorphous replacement and molecular replacement techniques. The atomic model was refined to anR-factor of 0.169 for 57,394 independent reflections. The spherical protein consists of four domains with a funnel-like cavity that leads to the freely accessible metal-ion redox center. The bis(molybdopterin guanine dinucleotide)molybdenum cofactor (1541 Da) of the single chain protein (85,033 Da) has the molybdenum ion bound to thecis-dithiolene group of only one molybdopterin guanine dinucleotide molecule. Three additional ligands, two oxo groups and the oxygen of a serine side-chain, are bound to the molybdenum ion. The second molybdopterin system is not part of the ligand sphere of the metal center with its sulfur atoms at distances of 3.5 Å and 3.8 Å away. It might be involved in electron shuttling from the protein surface to the molybdenum center.