Kobayashi T, Zhu Y F, Nicholls N J, Lampen J O
J Bacteriol. 1987 Sep;169(9):3873-8. doi: 10.1128/jb.169.9.3873-3878.1987.
A second regulatory locus (blaR1) required for the induction of beta-lactamase synthesis in Bacillus licheniformis 749 was cloned and sequenced. The gene was located on a 5.2-kilobase-pair SphI DNA fragment which also contained the beta-lactamase (blaP) and repressor (blaI) genes. Bacillus subtilis BD224 carrying these three genes synthesized beta-lactamase on exposure to cephalosporin C, whereas Escherichia coli HB101 carrying the genes did not show any detectable induction of the enzyme. An open reading frame of 1,803 bases was identified as the blaR1 gene by subcloning and DNA sequencing. The gene started 2 bases downstream of the termination codon of bla1 and was preceded by a putative Shine-Dalgarno sequence (AAGGA) with a spacing of 5 bases. The deduced blaR1 product (601 amino acids) had a molecular weight of 68,425. Five transmembrane regions were predicted from the hydrophobicity profile. The region around Phe-Ala-Pro-Ala-Ser-Thr-Tyr-Lys (amino acids 398 to 405), which appeared to be located outside the membrane, was homologous to the binding regions of penicillin-binding proteins, including the beta-lactamases. The segment of 22 amino acids from 400 to 421 showed more than 70% homology to the penicillin-binding region of PBP 2 of E. coli. The blaR1 gene encodes a potential penicillin receptor which is required for the induction of beta-lactamase in B. licheniformis 749.
克隆并测序了地衣芽孢杆菌749中诱导β-内酰胺酶合成所需的第二个调控基因座（blaR1）。该基因位于一个5.2千碱基对的SphI DNA片段上，该片段还包含β-内酰胺酶（blaP）和阻遏物（blaI）基因。携带这三个基因的枯草芽孢杆菌BD224在接触头孢菌素C时合成β-内酰胺酶，而携带这些基因的大肠杆菌HB101未显示出该酶的任何可检测到的诱导。通过亚克隆和DNA测序，一个1803个碱基的开放阅读框被鉴定为blaR1基因。该基因起始于bla1终止密码子下游2个碱基处，其前面有一个推定的Shine-Dalgarno序列（AAGGA），间隔为5个碱基。推导的blaR1产物（601个氨基酸）的分子量为68425。从疏水性图谱预测有五个跨膜区域。苯丙氨酸-丙氨酸-脯氨酸-丙氨酸-丝氨酸-苏氨酸-酪氨酸-赖氨酸（氨基酸398至405）周围的区域似乎位于膜外，与包括β-内酰胺酶在内的青霉素结合蛋白的结合区域同源。从400到421的22个氨基酸片段与大肠杆菌PBP 2的青霉素结合区域显示出超过70%的同源性。blaR1基因编码一种潜在的青霉素受体，它是地衣芽孢杆菌749中诱导β-内酰胺酶所必需的。
