Gomelsky M, Biville F, Gasser F, Tsygankov Y D
Institute of Genetics and Selection of Industrial Microorganisms, Moscow, Russia.
FEMS Microbiol Lett. 1996 Aug 1;141(2-3):169-76. doi: 10.1111/j.1574-6968.1996.tb08380.x.
Pyrroloquinoline quinone is a prosthetic group of bacterial methanol dehydrogenases as well as some alcohol and glucose dehydrogenases. Genes involved in pyrroloquinoline quinone production have previously been cloned from the representatives of the alpha and gamma subdivisions of the Proteobacteria. We report identification and the sequence of the pqqDGC gene cluster in the obligate methylotroph, Methylobacillus flagellatum, which belongs to the beta subdivision. The deduced products of the pqq genes from M. flagellatum appear to be more similar to their counterparts from non-methylotrophic species of the gamma subdivision than to a facultative methylotroph of the alpha subdivision. A non-polar mutation in pqqG was constructed and resulted in a strain impaired in growth on methanol. This mutant accumulated a detectable amount of intracellular pyrroloquinoline quinone, but in contrast to the wild type, did not excrete pyrroloquinoline quinone into the culture medium. The possible role of PqqG is discussed.
吡咯喹啉醌是细菌甲醇脱氢酶以及一些醇脱氢酶和葡萄糖脱氢酶的辅基。参与吡咯喹啉醌合成的基因先前已从变形菌门α和γ亚类的代表菌株中克隆出来。我们报道了专性甲基营养菌鞭毛甲基杆菌（属于β亚类）中pqqDGC基因簇的鉴定及序列。鞭毛甲基杆菌pqq基因的推导产物与γ亚类非甲基营养菌的对应产物相比，似乎比与α亚类的兼性甲基营养菌的对应产物更相似。构建了pqqG中的一个非极性突变体，该突变体导致菌株在甲醇上生长受损。该突变体积累了可检测到的细胞内吡咯喹啉醌，但与野生型不同的是，它没有将吡咯喹啉醌分泌到培养基中。文中讨论了PqqG的可能作用。
