Identification, characterization, and classification of genes encoding perchlorate reductase
Identification, characterization, and classification of genes encoding perchlorate reductase
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DOI：
10.1128/jb.187.15.5090-5096.2005
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发表时间：
2005-08-01
影响因子：
3.2
通讯作者：
Achenbach, LA
中科院分区：
文献类型：
--
作者：
Bender, KS;Shang, C;Achenbach, LA
高氯酸盐还原为亚氯酸盐是细菌还原高氯酸盐的第一步，由高氯酸盐还原酶催化。对两种十氯单胞菌编码高氯酸还原酶(PcrABCD)的基因进行了分析。对pcrAB基因产物的序列分析表明，它们与微生物硝酸还原酶、硒还原酶、二甲硫化物脱氢酶、乙苯脱氢酶和氯酸盐还原酶的α和β亚基相似，都是微生物二甲基亚砜(DMSO)还原酶家族的II型成员。PCRC基因产物类似于c型细胞色素，而pcrD基因产物与上述DMSO还原酶家族成员的钼伴侣蛋白相似。对激发性地氯单胞菌PcrA基因的表达分析表明，只有在厌氧(PER)氯酸盐还原条件下才能转录。无论是否存在高氯酸盐、氯酸盐或硝酸盐，氧气的存在都会完全抑制PcrA的表达。芳香十氯单胞菌中pcrA基因的缺失抑制了高氯酸盐和氯酸盐的生长，但不影响硝酸盐的生长，表明pcrABCD基因在高氯酸盐还原和硝酸盐还原中起着独立的作用。对DMSO还原酶家族的PcrA和其他α-亚基的系统发育分析表明，高氯酸盐还原酶是一个独立于十氯Ideonella dechloratans的氯酸盐还原酶的单系类群。以perA基因为探针的(Per)氯酸盐和氯酸盐还原菌株的DNA杂交分析进一步支持了高氯酸盐还原酶不同于氯酸盐还原酶的分离。
The reduction of perchlorate to chlorite, the first enzymatic step in the bacterial reduction of perchlorate, is catalyzed by perchlorate reductase. The genes encoding perchlorate reductase (pcrABCD) in two Dechloromonas species were characterized. Sequence analysis of the pcrAB gene products revealed similarity to alpha- and beta-subunits of microbial nitrate reductase, selenate reductase, dimethyl sulfide dehydrogenase, ethylbenzene dehydrogenase, and chlorate reductase, all of which are type II members of the microbial dimethyl sulfoxide (DMSO) reductase family. The pcrC gene product was similar to a c-type cytochrome, while the pcrD gene product exhibited similarity to molybdenum chaperone proteins of the DMSO reductase family members mentioned above. Expression analysis of the pcrA gene from Dechloromonas agitata indicated that transcription occurred only under anaerobic (per) chlorate-reducing conditions. The presence of oxygen completely inhibited pcrA expression regardless of the presence of perchlorate, chlorate, or nitrate. Deletion of the pcrA gene in Dechloromonas aromatica abolished growth in both perchlorate and chlorate but not growth in nitrate, indicating that the pcrABCD genes play a functional role in perchlorate reduction separate from nitrate reduction. Phylogenetic analysis of PcrA and other alpha-subumits of the DMSO reductase family indicated that perchlorate reductase forms a monophyletic group separate from chlorate reductase of Ideonella dechloratans. The separation of perchlorate reductase as an activity distinct from chlorate reductase was further supported by DNA hybridization analysis of (per)chlorate- and chlorate-reducing strains using the perA gene as a probe.