Springer A L, Auman A J, Lidstrom M E
Department of Chemical Engineering, University of Washington, Seattle 98195-1750, USA.
FEMS Microbiol Lett. 1998 Mar 1;160(1):119-24. doi: 10.1111/j.1574-6968.1998.tb12900.x.
In the facultative serine cycle methylotroph Methylobacterium extorquens AM1, mxaB is required for regulation of methanol oxidation and is located at the end of a large cluster of methylotrophy genes that begins with mxaF. The sequence of mxaB has been obtained and indicates that the gene product is a member of the response regulator family. None of the open reading frames near mxaB showed sequence identity to sensor kinases. Complementation studies suggest a promoter may be located adjacent to mxaB. Another gene (mxaW) is present immediately upstream of mxaF, divergently transcribed from a methanol-inducible promoter. The sequence in the region of mxaW was also obtained. MxaW showed no identity to known proteins. Mutations in mxaW and in an adjacent open reading frame, OrfR, had no effect on growth of M. extorquens AM1 on methanol or other substrates. The MxaW mutant had normal methanol dehydrogenase activity and normal transcription of the mxaF promoter. Therefore, the function of mxaW is unknown.
在兼性丝氨酸循环甲基营养菌嗜甲基甲基杆菌AM1中，mxaB是甲醇氧化调节所必需的，位于以mxaF起始的一大簇甲基营养基因的末端。已获得mxaB的序列，表明该基因产物是应答调节因子家族的成员。mxaB附近的开放阅读框均未显示与传感激酶的序列同一性。互补研究表明，一个启动子可能位于mxaB附近。另一个基因（mxaW）紧挨着mxaF的上游，从一个甲醇诱导型启动子反向转录。也获得了mxaW区域的序列。MxaW与已知蛋白质没有同一性。mxaW和相邻的开放阅读框OrfR中的突变对嗜甲基甲基杆菌AM1在甲醇或其他底物上的生长没有影响。MxaW突变体具有正常的甲醇脱氢酶活性和mxaF启动子的正常转录。因此，mxaW的功能尚不清楚。
