Fujimoto S, Clewell D B
Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
Proc Natl Acad Sci U S A. 1998 May 26;95(11):6430-5. doi: 10.1073/pnas.95.11.6430.
The Enterococcus faecalis conjugative plasmid pAD1 (60 kb) encodes a mating response to the recipient-produced peptide sex pheromone cAD1. The response involves two key plasmid-encoded regulatory proteins: TraE1, which positively regulates all or most structural genes relating to conjugation, and TraA, which binds DNA and negatively regulates expression of traE1. In vitro studies that included development of a DNA-associated protein-tag affinity chromatography technique showed that TraA (37.9 kDa) binds directly to cAD1 near its carboxyl-terminal end and, as a consequence, loses its affinity for DNA. Analyses of genetically modified TraA proteins indicated that truncations within the carboxyl-terminal 9 residues significantly affected the specificity of peptide-directed association/dissociation of DNA. The data support earlier observations that transposon insertions near the 3' end of traA eliminated the ability of cells to respond to cAD1.
粪肠球菌接合质粒pAD1（60 kb）编码对受体产生的肽性信息素cAD1的交配反应。该反应涉及两种关键的质粒编码调节蛋白：TraE1，它正向调节与接合相关的所有或大多数结构基因；TraA，它结合DNA并负向调节traE1的表达。包括开发一种与DNA相关的蛋白质标签亲和色谱技术在内的体外研究表明，TraA（37.9 kDa）在其羧基末端附近直接与cAD1结合，结果失去了对DNA的亲和力。对基因改造的TraA蛋白的分析表明，羧基末端9个残基内的截短显著影响了肽介导的DNA结合/解离的特异性。这些数据支持了早期的观察结果，即traA 3'端附近的转座子插入消除了细胞对cAD1作出反应的能力。
