The Tla protein of Porphyromonas gingivalis W50: a homolog of the RI protease precursor (PrpRI) is an outer membrane receptor required for growth on low levels of hemin
The Tla protein of Porphyromonas gingivalis W50: a homolog of the RI protease precursor (PrpRI) is an outer membrane receptor required for growth on low levels of hemin
复制标题
DOI：
10.1128/jb.179.15.4778-4788.1997
复制
发表时间：
1997-08-01
影响因子：
3.2
通讯作者：
Curtis, MA
中科院分区：
文献类型：
--
作者：
AduseOpoku, J;Slaney, JM;Curtis, MA
牙龈卟啉单胞菌 W50 的 prpR1 基因编码细胞外精氨酸特异性蛋白酶的多蛋白前体 (PrpRI)，PrpRI 被组织成四个不同的结构域（pro、α、β 和 γ），并被加工成异二聚体蛋白酶 (RI)，其中包含非共价连接的 α 和 β 组分。 α 组分包含蛋白酶活性位点，而 β 组分似乎具有作用在粘附和血凝过程中，与 RI beta 成分编码区同源的 DNA 序列存在于牙龈卟啉单胞菌染色体上的多个位点上，并且可能代表一个相关基因家族。在本报告中，我们描述了在质粒 pJM7 中分离的这些同源位点之一的克隆、序列分析和表征。pJM7 中的 6,041-bp 牙龈卟啉单胞菌 DNA 片段包含一个主要的开放阅读框3,291 bp，具有编码 M-r 118,700 蛋白质的潜力，推导序列的内部区域（V304 至 N768）与 PrpRI 的 β 结构域显示出 98% 的同一性，并且 pJM7 的重组产物与 RI β 成分特异性的抗体具有免疫反应性，推导序列的 N 末端与经常参与周质的 TonB 连接受体具有区域相似性氯高铁血红素、铁、大肠菌素或维生素 B-12 在其他细菌中的易位，因此我们将该基因命名为 tla（TonB 连接粘附素）。与亲本菌株相反，tla 插入失活的牙龈卟啉单胞菌 W50 的同基因突变体无法在含有低浓度氯化血红素的培养基中生长。
The prpR1 gene of Porphyromonas gingivalis W50 encodes the polyprotein precursor (PrpRI) of an extracellular arginine-specific protease, PrpRI is organized into four distinct domains (pro, alpha, beta, and gamma) and is processed to a heterodimeric protease (RI) which comprises the alpha and beta components in a noncovalent association, The alpha component contains the protease active site, whereas the beta component appears to have a role in adherence and hemagglutination processes, DNA sequences homologous to the coding region for the RI beta component are present at multiple loci on the P. gingivalis chromosome and may represent a family of related genes, In this report, we describe the cloning, sequence analysis, and characterization of one of these homologous loci isolated in plasmid pJM7, The 6,041-bp P. gingivalis DNA fragment in pJM7 contains a major open eading frame of 3,291 bp with coding potential for a protein with an M-r 118,700, An internal region of the deduced sequence (V304 to N768) shows 98% identity to the beta domain of PrpRI, and the recombinant product of pJM7 is immunoreactive with an antibody specific to the RI beta component, The N terminus of the deduced sequence has regional similarity to TonB-linked receptors which are frequently involved in periplasmic translocation of hemin, iron, colicins, or vitamin B-12 in other bacteria, We have therefore designated this gene tla (TonB linked adhesin). In contrast to the parent strain, an isogenic mutant of P. gingivalis W50 in which the tla was insertionally inactivated was unable to grow in medium containing low concentrations of hemin (