Inamine J M, Denny T P, Loechel S, Schaper U, Huang C H, Bott K F, Hu P C
Department of Pediatrics, University of North Carolina, Chapel Hill 27599-7220.
Gene. 1988 Apr 29;64(2):217-29. doi: 10.1016/0378-1119(88)90337-x.
The specific attachment of Mycoplasma pneumoniae to the respiratory ciliated epithelium is mediated by a surface protein designated P1. The nucleotide (nt) sequence of the P1 attachment-protein gene has been determined and the amino acid (aa) sequence deduced. mRNA and cDNA sequencing confirm that this gene is transcribed in M. pneumoniae. The predicted amino acid sequence matches the N-terminal 12 aa residues of P1 protein from M. pneumoniae [Jacobs et al., J. Gen. Microbiol. 133 (1987) 2233-2236] beginning with Asn at aa position 60, where aa 1 represents the first codon of the open reading frame (ORF). Notably, the Trp at aa position 69 aligns with a UGA codon deduced from the nucleotide sequence, providing supporting evidence that UGA is read as Trp rather than stop in M. pneumoniae. Analysis of the first 59 aa suggests that it is probably a leader sequence that is processed to yield the mature protein. The codons of the mature P1 protein sequence represent 1568 aa with a calculated Mr of 169,758. A unique feature of this protein sequence is the lack of cysteine, and this was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of M. pneumoniae proteins metabolically labeled with radioactive cysteine or methionine. This study has revealed that the 4881 nt of the P1 structural gene are flanked by ORFs, and there are no obvious ribosome-binding sites or transcription termination sequences in the immediately adjacent regions. This suggests that the P1 gene is transcribed as part of a larger polycistronic message. In addition, a number of untranscribed and therefore nonfunctional P1 epitope sequences were found in the M. pneumoniae genome; their purpose remains unknown.
肺炎支原体与呼吸道纤毛上皮的特异性附着是由一种名为P1的表面蛋白介导的。已确定P1附着蛋白基因的核苷酸（nt）序列并推导了氨基酸（aa）序列。mRNA和cDNA测序证实该基因在肺炎支原体中被转录。预测的氨基酸序列与肺炎支原体P1蛋白的N端12个aa残基匹配[Jacobs等人，《普通微生物学杂志》133（1987）2233 - 2236]，从aa位置60的Asn开始，其中aa 1代表开放阅读框（ORF）的第一个密码子。值得注意的是，aa位置69的Trp与从核苷酸序列推导的UGA密码子对齐，提供了支持证据表明在肺炎支原体中UGA被读作Trp而不是终止密码子。对前59个aa的分析表明它可能是一个前导序列，经加工后产生成熟蛋白。成熟P1蛋白序列的密码子代表1568个aa，计算的Mr为169,758。该蛋白序列的一个独特特征是缺乏半胱氨酸，这通过用放射性半胱氨酸或甲硫氨酸代谢标记的肺炎支原体蛋白的十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳得到证实。这项研究表明，P1结构基因的4881 nt两侧是ORF，并且在紧邻区域没有明显的核糖体结合位点或转录终止序列。这表明P1基因作为更大的多顺反子信息的一部分被转录。此外，在肺炎支原体基因组中发现了许多未转录因此无功能的P1表位序列；它们的用途仍然未知。
