THE VANA GLYCOPEPTIDE RESISTANCE PROTEIN IS RELATED TO D-ALANYL-D-ALANINE LIGASE CELL-WALL BIOSYNTHESIS ENZYMES
THE VANA GLYCOPEPTIDE RESISTANCE PROTEIN IS RELATED TO D-ALANYL-D-ALANINE LIGASE CELL-WALL BIOSYNTHESIS ENZYMES
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DOI：
10.1007/bf00262430
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发表时间：
1990-12-01
期刊：
影响因子：
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通讯作者：
COURVALIN, P
中科院分区：
文献类型：
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作者：
DUTKAMALEN, S;MOLINAS, C;COURVALIN, P
屎肠球菌菌株BM 4147中质粒pIP 816介导了对糖肽类抗生素万古霉素和替考拉宁的诱导耐药性。万古霉素诱导了CA的合成。40 kDa膜相关蛋白，命名为VANA。部分纯化了抗性蛋白，并测定了其N端序列。将pIP 816的一个1761 bp的DNA限制性片段克隆到大肠杆菌中并测序。当在E. coli中，该片段编码一个ca.与来自肠球菌膜组分的VANA共迁移的40 kDa蛋白。VANA的ATG翻译起始密码子指定了存在于蛋白质N-末端的甲硫氨酸，表明不存在信号肽加工。从vanA基因的序列推导的氨基酸序列由343个氨基酸组成，得到具有37400的计算Mr的蛋白质。VANA在结构上与鼠伤寒沙门氏菌（36%氨基酸同一性）和大肠杆菌（30%氨基酸同一性）的D-丙氨酰-D-丙氨酸（D-ala-D-ala）连接酶相关。大肠杆菌（28%）。vanA基因能够反式互补E.大肠杆菌突变株，具有温敏D-ala-D-ala连接酶活性。因此，可诱导的抗性蛋白VANA在结构和功能上与合成糖肽类抗生素靶点的细胞质酶相关。基于这些观察结果，我们讨论的可能性，耐药是由于修改的糖肽目标。
Inducible resistance to the glycopeptide antibiotics vancomycin and teicoplanin is mediated by plasmid pIP816 in Enterococcus faecium strain BM4147. Vancomycin induced the synthesis of a ca. 40 kDa membrane-associated protein designated VANA. The resistance protein was partially purified and its N-terminal sequence was determined. A 1761 bp DNA restriction fragment of pIP816 was cloned into Escherichia coli and sequenced. When expressed in E. coli, this fragment encoded a ca. 40 kDa protein that comigrated with VANA from enterococcal membrane fractions. The ATG translation initiation codon for VANA specified the methionine present at the N-terminus of the protein indicating the absence of signal peptide processing. The amino acid sequence deduced from the sequence of the vanA gene consisted of 343 amino acids giving a protein with a calculated Mr of 37400. VANA was structurally related to the D-alanyl-D-alanine (D-ala-D-ala) ligases of Salmonella typhimurium (36% amino acid identity) and of E. coli (28%). The vanA gene was able to transcomplement an E. coli mutant with thermosensitive D-ala-D-ala ligase activity. Thus, the inducible resistance protein VANA was structurally and functionally related to cytoplasmic enzymes that synthesize the target of glycopeptide antibiotics. Based on these observations we discuss the possibility that resistance is due to modification of the glycopeptide target.