Ladefoged S A, Birkelund S, Hauge S, Brock B, Jensen L T, Christiansen G
Department of Medical Microbiology and Immunology, University of Aarhus, Denmark.
Infect Immun. 1995 Jan;63(1):212-23. doi: 10.1128/iai.63.1.212-223.1995.
A monoclonal antibody was used to characterize a 135-kDa surface-located membrane protein (Lmp1) generally present in Mycoplasma hominis strains. The monoclonal antibody, 552, was applied to identify the corresponding gene in an expression library of M. hominis PG21 DNA. The M. hominis PG21 lmp1 gene was sequenced, and its gene product was characterized with the goal of elucidating the structure and function of Lmp1. A total of 7,196 bp in the lmp1 region was sequenced. An open reading frame of 4,032 bp, encoding a protein of 1,344 amino acids with a calculated molecular weight of 147,000, was identified. Analysis of the deduced amino acid sequence predicted a hydrophilic protein with a basic pI (10.0). The N-terminal 24 amino acids were a typical leader sequence. Downstream from the first 726 nucleotides, six similar direct repeats of 471 nucleotides were found. In repeat 7, a single-base substitution, C-->A, gave rise to the stop codon of lmp1. Thus, the C-terminal 945 amino acids were encoded by the 471-bp direct repeats. As evidenced by Southern blot analysis, the gene encoding the 135-kDa antigen is part of a multigene family. One of the genes, lmp2, was situated directly downstream from lmp1 where the direct repeats continued.
一种单克隆抗体被用于鉴定一种通常存在于人型支原体菌株中的135 kDa表面定位膜蛋白（Lmp1）。该单克隆抗体552被用于在人型支原体PG21 DNA的表达文库中鉴定相应基因。对人型支原体PG21的lmp1基因进行了测序，并对其基因产物进行了表征，目的是阐明Lmp1的结构和功能。lmp1区域总共测序了7196 bp。鉴定出一个4032 bp的开放阅读框，编码一个1344个氨基酸的蛋白质，计算分子量为147,000。对推导的氨基酸序列分析预测这是一种具有碱性pI（10.0）的亲水性蛋白质。N端的24个氨基酸是典型的前导序列。在最初的726个核苷酸下游，发现了6个471个核苷酸的相似直接重复序列。在重复序列7中，一个单碱基替换C→A产生了lmp1的终止密码子。因此，C端的945个氨基酸由471 bp的直接重复序列编码。Southern印迹分析表明，编码135 kDa抗原的基因是一个多基因家族的一部分。其中一个基因lmp2直接位于lmp1的下游，直接重复序列在那里继续。
