The Bla2 β-lactamase from the live-vaccine strain of Francisella tularensis encodes a functional protein that is only active against penicillin-class β-lactam antibiotics
The Bla2 β-lactamase from the live-vaccine strain of Francisella tularensis encodes a functional protein that is only active against penicillin-class β-lactam antibiotics
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DOI：
10.1007/s00203-006-0140-6
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发表时间：
2006-09-01
影响因子：
2.8
通讯作者：
Bina, James E.
中科院分区：
文献类型：
--
作者：
Bina, Xiaowen R.;Wang, Chunmei;Bina, James E.
土拉菌。土拉菌是一种a类选择剂，是人畜共患疾病土拉菌病的致病生物。绝大多数土拉菌分离株是β -内酰胺酶阳性。β -内酰胺酶的产生被广泛认为是导致β -内酰胺类药物治疗兔热病无效的原因。在这项研究中，我们报道了两条染色体编码的土拉菌ssp的克隆和鉴定。holarctica活疫苗菌株(LVS) β -内酰胺酶。这两种LVS β -内酰胺酶与F. tularensis Schu S4开放阅读框FTT0681c和FTT0611c同源，分别命名为bla1（LVS）和bla2（LVS）。在大肠杆菌中的重组表达表明，bla1 （LVS）不编码功能性β -内酰胺酶，而bla2 （LVS）编码功能性β -内酰胺酶，该酶可水解青霉素，但对第三代头孢菌素（包括头孢丙烯）无活性。针对LVS和Schu S4对头孢丙烯敏感的特点，我们在筛选的基础上开发了3种新的穿梭载体，用于用头孢丙烯生产Bla（shv-2）广谱β -内酰胺酶。所得到的穿梭载体适合于重组基因在LVS和Schu S4中的表达和互补研究。
Francisella tularensis ssp. tularensis is a category A select agent and the causal organism for the zoonotic disease tularemia. The vast majority of F. tularensis isolates are beta-lactamase-positive. beta-lactamase production is widely believed to be responsible for the inefficacy of beta-lactams in the treatment of tularemia. In this study, we report the cloning and characterization of the two chromosomally encoded F. tularensis ssp. holarctica live-vaccine strain (LVS) beta-lactamases. The two LVS beta-lactamases were homologous to F. tularensis Schu S4 open reading frames FTT0681c and FTT0611c and have been named bla1(LVS) and bla2(LVS) , respectively. Recombinant expression in Escherichia coli suggested that bla1 (LVS) did not encode a functional beta-lactamase, whereas bla2 (LVS) encoded a functional beta-lactamase that hydrolyzed penicillins but was inactive against third-generation cephalosporins, including cefprozil. As both LVS and Schu S4 were susceptible to cefprozil, we developed three new shuttle vectors based on selection for the production of the Bla(shv-2) extended-spectrum beta-lactamase with cefprozil. The resulting shuttle vectors were suitable for recombinant gene expression and complementation studies in LVS and Schu S4.