el Kharroubi A, Jacques P, Piras G, Van Beeumen J, Coyette J, Ghuysen J M
Centre d'Ingénierie des Protéines, Université de Liège, Belgium.
Biochem J. 1991 Dec 1;280 ( Pt 2)(Pt 2):463-9.
The penicillin-resistant Enterococcus hirae R40 has a typical profile of membrane-bound penicillin-binding proteins (PBPs) except that the 71 kDa PBP5 of low penicillin affinity represents about 50% of all the PBPs present. Water-soluble tryptic-digest peptides were selectively produced from PBP5, their N-terminal regions were sequenced and synthetic oligonucleotides were used as primers to generate a 476 bp DNA fragment by polymerase chain reaction. On the basis of these data, the PBP5-encoding gene was cloned in Escherichia coli by using pBR322 as vector. The gene, included in a 7.1 kb insert, had the information for a 678-amino acid-residue protein. PBP5 shows similarity, in the primary structure, with the high-molecular-mass PBPs of class B. In particular, amino acid alignment of the enterococcal PBP5 and the methicillin-resistant staphylococcal PBP2' generates scores that are 30, for the N-terminal domains, and 53, for the C-terminal domains, standard deviations above that expected for a run of 20 randomized pairs of proteins having the same amino acid compositions as the two proteins under consideration.
耐青霉素的希拉肠球菌R40具有典型的膜结合青霉素结合蛋白（PBPs）谱，只是低青霉素亲和力的71 kDa PBP5约占所有存在的PBPs的50%。从PBP5中选择性地产生水溶性胰蛋白酶消化肽，对其N端区域进行测序，并使用合成寡核苷酸作为引物，通过聚合酶链反应产生一个476 bp的DNA片段。基于这些数据，以pBR322为载体，将编码PBP5的基因克隆到大肠杆菌中。该基因包含在一个7.1 kb的插入片段中，具有编码一个678个氨基酸残基蛋白质的信息。PBP5在一级结构上与B类高分子量PBPs相似。特别是，肠球菌PBP5和耐甲氧西林葡萄球菌PBP2'的氨基酸比对，N端结构域的得分是30，C端结构域的得分是53，比具有与所考虑的两种蛋白质相同氨基酸组成的20对随机蛋白质序列预期的标准差高。
