Signoretto C, Boaretti M, Canepari P
Istituto di Microbiologia, Università di Verona, Italy.
FEMS Microbiol Lett. 1994 Oct 15;123(1-2):99-106. doi: 10.1111/j.1574-6968.1994.tb07207.x.
Low-affinity penicillin binding proteins are particular membrane proteins, in several Gram-positive bacteria, which are involved in beta-lactam antibiotic resistance. The structural gene for the low-affinity penicillin binding protein 5 (PBP5) of Enterococcus faecalis was cloned and sequenced. From the sequence of the 3378 bp, a 2040 bp coding region was identified. From biochemical analysis it emerges that E. faecalis PBP5 is a type II membrane protein with an uncleaved N-terminal and is composed of 679 amino acids with a molecular weight of 74055. This protein showed 48 and 33% of identity with Enterococcus hirae PBP5 and Staphylococcus aureus PBP2a, both low-affinity PBPs involved in beta-lactam resistance. Anti-PBP5 antibodies cross-reacted with a membrane protein present in other species of enterococci, but the entire gene fragment cloned hybridized only with DNAs of E. faecalis strains, thus suggesting that genes coding for low-affinity PBPs of enterococci are not strictly homologous. In this experiment digoxigenin-labelled E. faecalis DNA was used.
低亲和力青霉素结合蛋白是几种革兰氏阳性细菌中特定的膜蛋白，与β-内酰胺抗生素耐药性有关。粪肠球菌低亲和力青霉素结合蛋白5（PBP5）的结构基因被克隆并测序。从3378 bp的序列中，鉴定出一个2040 bp的编码区。生化分析表明，粪肠球菌PBP5是一种II型膜蛋白，N端未切割，由679个氨基酸组成，分子量为74055。该蛋白与平肠球菌PBP5和金黄色葡萄球菌PBP2a分别有48%和33%的同源性，这两种低亲和力PBP都与β-内酰胺耐药性有关。抗PBP5抗体与其他肠球菌物种中存在的一种膜蛋白发生交叉反应，但克隆的整个基因片段仅与粪肠球菌菌株的DNA杂交，因此表明编码肠球菌低亲和力PBP的基因并非严格同源。在本实验中使用了地高辛标记的粪肠球菌DNA。
