Huang Y X, Ching G, Inouye M
J Biol Chem. 1983 Jul 10;258(13):8139-45.
A DNA sequence of 532 base pairs encompassing the entire Morganella morganii lipoprotein gene (lpp) was determined. Sequence comparisons of the M. morganii lpp gene with the lpp genes from Escherichia coli, Serratia marcescens, and Erwinia amylovora reveal that the M. morganii lpp gene is more distantly related to the E. coli lpp gene than any of the other lpp genes examined. Between the E. coli and M. morganii lpp genes, the following homologies were found: 44% in the promoter region (bases, -45 to -1), 88% in the 5'-end untranslated region of the mRNA, 58% in the signal sequence coding region, 75% in the coding region for the first 51 and 43% for the last 7 amino acid residues. Upstream of the promoter region and downstream of the termination codon, there are extensive insertions, deletions, and base substitutions. In spite of the differences in the DNA sequences, the lipoprotein structure was found to be highly conserved except for the carboxyl-terminal sequence of 7 amino residues. The coding region of the M. morganii lpp gene including the signal sequence was inserted into an expression cloning vector so that the production of the M. morganii lipoprotein could be induced in E. coli by a lac inducer, isopropyl-beta-D-thioglactoside. It was found that when induced, the M. morganii prolipoprotein was apparently secreted normally across the E. coli cytoplasmic membrane, modified with glycerol and palmitic acid, processed to the mature lipoprotein, and assembled in the E. coli outer membrane. The bound form covalently linked to the peptidoglycan was also found.
测定了一段包含摩根氏摩根菌脂蛋白基因（lpp）全长的532个碱基对的DNA序列。将摩根氏摩根菌lpp基因与大肠杆菌、粘质沙雷氏菌和梨火疫欧文氏菌的lpp基因进行序列比较，发现摩根氏摩根菌lpp基因与大肠杆菌lpp基因的亲缘关系比所检测的其他任何lpp基因都更远。在大肠杆菌和摩根氏摩根菌的lpp基因之间，发现了以下同源性：启动子区域（碱基-45至-1）为44%，mRNA的5'-端非翻译区为88%，信号序列编码区为58%，前51个氨基酸编码区为75%，最后7个氨基酸残基编码区为43%。在启动子区域上游和终止密码子下游，存在大量的插入、缺失和碱基替换。尽管DNA序列存在差异，但除了7个氨基酸残基的羧基末端序列外，脂蛋白结构被发现高度保守。将包含信号序列的摩根氏摩根菌lpp基因编码区插入表达克隆载体，以便通过乳糖诱导剂异丙基-β-D-硫代半乳糖苷在大肠杆菌中诱导产生摩根氏摩根菌脂蛋白。结果发现，诱导后，摩根氏摩根菌前脂蛋白显然能正常分泌穿过大肠杆菌细胞质膜，经甘油和棕榈酸修饰，加工成成熟脂蛋白，并组装在大肠杆菌外膜中。还发现了与肽聚糖共价连接的结合形式。
