Ansai T, Yamashita Y, Awano S, Shibata Y, Wachi M, Nagai K, Takehara T
Department of Preventive Dentistry, Kyushu Dental College, Kitakyushu, Japan.
Microbiology (Reading). 1995 Sep;141 ( Pt 9):2047-52. doi: 10.1099/13500872-141-9-2047.
The gene encoding a 51 kDa polypeptide of Porphyromonas gingivalis 381 was isolated by immunoblotting using an antiserum raised against P. gingivalis alkaline phosphatase. DNA sequence analysis of a 2.5 kb DNA fragment containing a gene encoding the 51 kDa protein revealed one complete and two incomplete ORFs. Database searches using the FASTA program revealed significant homology between the P. gingivalis 51 kDa protein and the MurC protein of Escherichia coli, which functions in peptidoglycan synthesis. The cloned 51 kDa protein encoded a functional product that complemented an E. coli murC mutant. Moreover, the ORF just upstream of murC coded for a protein that was 31% homologous with the E. coli MurG protein. The ORF just downstream of murC coded for a protein that was 17% homologous with the Streptococcus pneumoniae penicillin-binding protein 2B (PBP2B), which functions in peptidoglycan synthesis and is responsible for antibiotic resistance. These results suggest that P. gingivalis contains a homologue of the E. coli peptidoglycan synthesis gene murC and indicate the possibility of a cluster of genes responsible for cell division and cell growth, as in the E. coli mra region.
利用针对牙龈卟啉单胞菌381碱性磷酸酶产生的抗血清，通过免疫印迹法分离出编码牙龈卟啉单胞菌381 51 kDa多肽的基因。对一个包含编码51 kDa蛋白质基因的2.5 kb DNA片段进行DNA序列分析，发现一个完整的开放阅读框（ORF）和两个不完整的ORF。使用FASTA程序进行数据库搜索发现，牙龈卟啉单胞菌51 kDa蛋白质与大肠杆菌中参与肽聚糖合成的MurC蛋白之间存在显著同源性。克隆的51 kDa蛋白质编码一种功能性产物，可互补大肠杆菌murC突变体。此外，murC上游的ORF编码一种与大肠杆菌MurG蛋白有31%同源性的蛋白质。murC下游的ORF编码一种与肺炎链球菌青霉素结合蛋白2B（PBP2B）有17%同源性的蛋白质，PBP2B参与肽聚糖合成并与抗生素耐药性有关。这些结果表明牙龈卟啉单胞菌含有大肠杆菌肽聚糖合成基因murC的同源物，并提示存在一个负责细胞分裂和细胞生长的基因簇的可能性，如同大肠杆菌的mra区域。
