Oxygen reduction in the strict anaerobe Desulfovibrio vulgaris Hildenborough: characterization of two membrane-bound oxygen reductases
Oxygen reduction in the strict anaerobe Desulfovibrio vulgaris Hildenborough: characterization of two membrane-bound oxygen reductases
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DOI：
10.1099/mic.0.049171-0
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发表时间：
2011-09-01
期刊：
影响因子：
2.8
通讯作者：
Brasseur, G.
中科院分区：
文献类型：
--
作者：
Lamrabet, O.;Pieulle, L.;Brasseur, G.
虽然脱硫弧菌是一种严格的厌氧细菌，但它能够在不同的细胞区室中消耗氧气，包括用氢作为电子供体进行广泛的周质O（2）还原。DvH的基因组揭示了cydAB和考克斯基因的存在，分别编码醌醇氧化酶bd和细胞色素c氧化酶。在DvH的膜中，我们检测到喹啉氧还原酶[被庚基-羟基喹啉-N-氧化物（HQNO）抑制]和细胞色素c氧化酶活性。膜级分的光谱和HPLC数据显示，除了大多数C型血红素外，还存在o-、B-和d-型血红素，但没有a-型血红素，这与一氧化碳结合分析一致。因此，细胞色素c氧化酶是cc（o/B）o（3）型，这是一种以前没有描述过的类型。单血红素细胞色素C（553）是细胞色素c氧化酶的电子供体;其编码基因位于考克斯操纵子的上游，比编码细胞色素c氧化酶亚基I的cox I转录多50倍。即使当DvH在厌氧条件下在乳酸盐/硫酸盐培养基中生长时，两个末端氧化酶编码基因也表达。此外，醌醇氧化酶bd编码基因比考克斯基因表达更高。考克斯操纵子表现出非典型的基因组组织，coxII基因位于coxIV的下游。这些膜结合的氧还原酶在其他严格厌氧Deltaproteobacteria的发生进行了讨论。
Although Desulfovibrio vulgaris Hildenborough (DvH) is a strictly anaerobic bacterium, it is able to consume oxygen in different cellular compartments, including extensive periplasmic O(2) reduction with hydrogen as electron donor. The genome of DvH revealed the presence of cydAB and cox genes, encoding a quinol oxidase bd and a cytochrome c oxidase, respectively. In the membranes of DvH, we detected both quinol oxygen reductase [inhibited by heptyl-hydroxyquinoline-N-oxide (HQNO)] and cytochrome c oxidase activities. Spectral and HPLC data for the membrane fraction revealed the presence of o-, b- and d-type haems, in addition to a majority of c-type haems, but no a-type haem, in agreement with carbon monoxide-binding analysis. The cytochrome c oxidase is thus of the cc(o/b)o(3) type, a type not previously described. The monohaem cytochrome C(553) is an electron donor to the cytochrome c oxidase; its encoding gene is located upstream of the cox operon and is 50-fold more transcribed than coxI encoding the cytochrome c oxidase subunit I. Even when DvH is grown under anaerobic conditions in lactate/sulfate medium, the two terminal oxidase-encoding genes are expressed. Furthermore, the quinol oxidase bd-encoding genes are more highly expressed than the cox genes. The cox operon exhibits an atypical genomic organization, with the gene coxII located downstream of coxIV. The occurrence of these membrane-bound oxygen reductases in other strictly anaerobic Deltaproteobacteria is discussed.