Cell wall monoglycine cross-bridges and methicillin hypersusceptibility in a femAB null mutant of methicillin-resistant Staphylococcus aureus
Cell wall monoglycine cross-bridges and methicillin hypersusceptibility in a femAB null mutant of methicillin-resistant Staphylococcus aureus
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DOI：
10.1128/jb.179.1.9-16.1997
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发表时间：
1997-01-01
影响因子：
3.2
通讯作者：
BergerBachi, B
中科院分区：
文献类型：
--
作者：
Stranden, AM;Ehlert, K;BergerBachi, B
femAB操纵子参与葡萄球菌肽聚糖的特征性五甘氨酸侧链的形成。在耐甲氧西林金黄色葡萄球菌菌株中，四环素抗性决定子tetK对femAB操纵子的等位基因替换导致生长受损、甲氧西林过敏性和溶葡萄球菌酶抗性。通常的五甘氨酸交叉桥仅被单甘氨酸桥替换，肽聚糖链的交联显著减少。femA或femAB对femAB无效突变体的互补导致交叉桥分别延伸至三甘氨酸或五甘氨酸。这一发现表明，FemA负责肽聚糖前体的五甘氨酸侧链的甘氨酸2和3的形成，FemB负责肽聚糖前体的五甘氨酸侧链的甘氨酸4和5的形成。此外，可以推断，第一个甘氨酸的添加必须通过非femAB依赖性机制发生。
The femAB operon is involved in the formation of the characteristic pentaglycine side chain of the staphylococcal peptidoglycan. Allele replacement of the femAB operon with the tetracycline resistance determinant tetK in a methicillin-resistant Staphylococcus aureus strain resulted in impaired growth, methicillin hypersusceptibility, and lysostaphin resistance, The usual pentaglycine cross-bridges were replaced by monoglycine bridges exclusively, and cross-linking of the peptidoglycan strands was drastically reduced. Complementation of the femAB null mutant by either femA or femAB resulted in the extension of the cross-bridges to a triglycine or a pentaglycine, respectively. This finding suggests that FemA is responsible for the formation of glycines 2 and 3, and FemB is responsible for formation of glycines 4 and 5, of the pentaglycine side chain of the peptido-glycan precursor. Moreover, it can be deduced that addition of the first glycine must occur by a femAB-independent mechanism.