Ruhfel R E, Manias D A, Dunny G M
Institute for Advanced Studies in Biological Process Technology, University of Minnesota, St. Paul 55108.
J Bacteriol. 1993 Aug;175(16):5253-9. doi: 10.1128/jb.175.16.5253-5259.1993.
In order to investigate the mechanism by which peptide sex pheromones induce expression of the conjugation functions of certain Enterococcus faecalis plasmids, a biological assay was developed to measure the ability of cells carrying the conjugative plasmid pCF10 to bind the sex pheromone cCF10. The data indicated that pCF10 endows its host E. faecalis cell with the ability to specifically remove (apparently by irreversible binding) cCF10 activity from culture medium. The pCF10 DNA encoding this ability was localized to a 3.4-kb segment within a region involved in negative control of expression of conjugal transfer functions. This segment also encoded ability to bind the pheromone inhibitor peptide iCF10. DNA sequencing revealed three open reading frames, which have been denoted prgW (pheromone responsive gene W), prgZ, and prgY. The deduced product of prgW resembled regulatory proteins from other bacteria and eucaryotes, with a very high degree of identity within a putative DNA-binding domain. The prgY gene actually extended into an adjacent region of pCF10 and could encode a protein with significant similarity to a protein called TraB, believed to be involved in shutdown of pheromone cAD1 production by cells carrying the pheromone-inducible hemolysin plasmid pAD1, according to F.Y. An and D.B. Clewell (Abstr. Gen. Meet. Am. Soc. Microbiol. 1992, H70, 1992). The prgZ gene product showed significant relatedness to binding proteins encoded by oligopeptide permease (opp) operons in gram-positive and gram-negative bacteria and is highly similar to a pAD1-encoded protein, TraC, which is believed to mediate sex pheromone cAD1 binding (K. Tanimoto, F. Y. An, and D. B. Clewell, submitted for publication). A Tn5 insertion into prgZ abolished cCF10 binding ability.
为了研究肽类性信息素诱导某些粪肠球菌质粒接合功能表达的机制，开发了一种生物学检测方法，以测量携带接合质粒pCF10的细胞结合性信息素cCF10的能力。数据表明，pCF10赋予其宿主粪肠球菌细胞从培养基中特异性去除（显然是通过不可逆结合）cCF10活性的能力。编码这种能力的pCF10 DNA定位于参与接合转移功能表达负调控的区域内一个3.4 kb的片段。该片段还编码结合信息素抑制剂肽iCF10的能力。DNA测序揭示了三个开放阅读框，分别命名为prgW（信息素响应基因W）、prgZ和prgY。prgW推导的产物类似于来自其他细菌和真核生物的调节蛋白，在一个假定的DNA结合结构域内具有很高的同源性。prgY基因实际上延伸到pCF10的相邻区域，根据F.Y. An和D.B. Clewell（《美国微生物学会年会摘要》，1992年，H70，1992）的研究，它可能编码一种与名为TraB的蛋白质具有显著相似性的蛋白质，据信TraB参与携带信息素诱导的溶血素质粒pAD1的细胞关闭信息素cAD1的产生。prgZ基因产物与革兰氏阳性和革兰氏阴性细菌中寡肽通透酶（opp）操纵子编码的结合蛋白有显著相关性，并且与一种pAD1编码的蛋白质TraC高度相似，据信TraC介导性信息素cAD1的结合（K. Tanimoto、F.Y. An和D.B. Clewell，已提交发表）。Tn5插入prgZ会消除cCF10的结合能力。
