Inamine J M, Loechel S, Collier A M, Barile M F, Hu P C
Department of Pediatrics, University of North Carolina, Chapel Hill 27599-7220.
Gene. 1989 Oct 30;82(2):259-67. doi: 10.1016/0378-1119(89)90051-6.
The attachment of Mycoplasma genitalium and Mycoplasma pneumoniae to ciliated epithelium involves two surface proteins designated MgPa and P1, respectively. We have previously cloned and sequenced the P1 (mpp) operon of M. pneumoniae, and report here the use of P1-derived probes to clone and sequence a 10.4-kb region of M. genitalium DNA that, by analogy to the P1 operon, contains the MgPa (mgp) operon. The deduced amino acid sequences of the 29-kDa (ORF-1), MgPa (160-kDa) and 114-kDa (ORF-3) proteins of the MgPa operon show extensive homologies with those of the 28-kDa, P1 (170-kDa) and 130-kDa proteins, respectively, encoded by the P1 operon. The common features and homology of these operons are consistent with previous observations that the MgPa and P1 proteins share cross-reactive epitopes, as well as similar biological function. The gene order of the MgPa operon is ORF-1, MgPa, ORF-3, with intervening regions of 6 and 1 nt, respectively. A consensus ribosome-binding site (RBS) sequence is found before ORF-1 and a sequence indicative of a transcription terminator is located beyond ORF-3; the absence of such sequences adjacent to the MgPa gene suggests that the operon is transcribed as a polycistronic message. The RBS sequence is followed by sequences of dyad symmetry that have the potential to form two alternative stem-and-loop structures, which could be involved in controlling initiation of translation.
生殖支原体和肺炎支原体与纤毛上皮的附着分别涉及两种表面蛋白，分别命名为MgPa和P1。我们之前已克隆并测序了肺炎支原体的P1（mpp）操纵子，在此报告使用P1衍生探针克隆并测序生殖支原体DNA的一个10.4 kb区域，该区域类似于P1操纵子，包含MgPa（mgp）操纵子。MgPa操纵子的29 kDa（ORF-1）、MgPa（160 kDa）和114 kDa（ORF-3）蛋白的推导氨基酸序列分别与P1操纵子编码的28 kDa、P1（170 kDa）和130 kDa蛋白的氨基酸序列具有广泛的同源性。这些操纵子的共同特征和同源性与之前的观察结果一致，即MgPa和P1蛋白共享交叉反应性表位以及相似的生物学功能。MgPa操纵子的基因顺序为ORF-1、MgPa、ORF-3，中间区域分别为6和1个核苷酸。在ORF-1之前发现了一个共有核糖体结合位点（RBS）序列，并且在ORF-3之后定位了一个指示转录终止子的序列；MgPa基因附近没有此类序列，这表明该操纵子作为多顺反子信息进行转录。RBS序列之后是具有形成两种交替茎环结构潜力的二元对称序列，这可能参与控制翻译起始。
