Mottl H, Terpstra P, Keck W
Dept. of Biochemistry, University of Groningen, The Netherlands.
FEMS Microbiol Lett. 1991 Mar 1;62(2-3):213-20. doi: 10.1016/0378-1097(91)90160-c.
The nucleotide sequence of a 1884 bp DNA fragment of E. coli, carrying the gene dacB, was determined. The DNA codes for penicillin-binding protein 4 (PBP4), an enzyme of 477 amino acids, being involved as a DD-carboxypeptidase-endopeptidase in murein metabolism. The enzyme is translated with a cleavable signal peptide of 20 amino acids, which was verified by sequencing the amino-terminus of the isolated protein. The characteristic active-site fingerprints SXXK, SXN and KTG of class A beta-lactamases and penicillin-binding proteins were located in the sequence. On the basis of amino acid alignments we propose, that PBP4 and class A beta-lactamases share a common evolutionary origin but PBP4 has acquired an additional domain of 188 amino acids in the region between the SXXK and SXN elements.
测定了大肠杆菌中携带dacB基因的一段1884 bp DNA片段的核苷酸序列。该DNA编码青霉素结合蛋白4（PBP4），一种由477个氨基酸组成的酶，作为DD-羧肽酶-内肽酶参与胞壁质代谢。该酶由一个可裂解的20个氨基酸的信号肽翻译而来，这通过对分离蛋白的氨基末端进行测序得到了验证。A类β-内酰胺酶和青霉素结合蛋白的特征性活性位点指纹SXXK、SXN和KTG位于该序列中。基于氨基酸序列比对，我们提出PBP4和A类β-内酰胺酶具有共同的进化起源，但PBP4在SXXK和SXN元件之间的区域获得了一个额外的188个氨基酸的结构域。
