Adaptation of Pseudomonas aeruginosa to various conditions includes tRNA-dependent formation of alanyl-phosphatidylglycerol
Adaptation of Pseudomonas aeruginosa to various conditions includes tRNA-dependent formation of alanyl-phosphatidylglycerol
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DOI：
10.1111/j.1365-2958.2008.06562.x
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发表时间：
2009-02-01
影响因子：
3.6
通讯作者：
Moser, Juergen
中科院分区：
文献类型：
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作者：
Klein, Stefanie;Lorenzo, Carlos;Moser, Juergen
当暴露于酸性生长条件时，条件性细菌铜绿假单胞菌合成大量的额外磷脂，鉴定为2'丙氨酰磷脂酰甘油（A-PG）。在pH 5.3时，A-PG占细菌总脂质含量的6%。铜绿假单胞菌的序列分析揭示了开放阅读框PA 0920，其与来自金黄色葡萄球菌的参与赖氨酰磷脂酰甘油的tRNA依赖性形成的蛋白质具有34%的序列同一性。铜绿假单胞菌缺失突变株Δ PA 0920不能合成A-PG，而在大肠杆菌中，PA 0920的异源性过量生产导致了大量的A-PG的形成，而在其它情况下，大肠杆菌不能合成A-PG。杆菌因此，PA 0920编码的蛋白质被命名为A-PG合成酶。该酶被鉴定为内膜的组成部分。通过去污剂溶解部分纯化蛋白质，并进行体外活性测定。证明了tRNA（Ala）依赖的催化作用。在不同pH条件下，使用lacZ报告基因融合物对铜绿假单胞菌中相应基因的转录分析表明，酸激活的转录为4.4倍。表型微阵列分析用于鉴定A-PG功能的进一步条件。
The opportunistic bacterium Pseudomonas aeruginosa synthesizes significant amounts of an additional phospholipid, identified as 2' alanylphosphatidylglycerol (A-PG), when exposed to acidic growth conditions. At pH 5.3 A-PG contributed up to 6% to the overall lipid content of the bacterium. Sequence analysis of P. aeruginosa revealed open reading frame PA0920 showing 34% sequence identity to a protein from Staphylococcus aureus involved in tRNA-dependent formation of lysylphosphatidylglycerol. The P. aeruginosa deletion mutant Delta PA0920 failed to synthesize A-PG. Heterologous overproduction of PA0920 in Escherichia coli resulted in the formation of significant amounts of A-PG, otherwise not synthesized by E. coli. Consequently, the protein encoded by PA0920 was named A-PG synthase. The enzyme was identified as an integral component of the inner membrane. The protein was partially purified by detergent solubilization and subjected to an in vitro activity assay. tRNA(Ala)-dependent catalysis was demonstrated. Transcriptional analysis of the corresponding gene in P. aeruginosa using lacZ reporter gene fusion under various pH conditions indicated a 4.4-fold acid-activated transcription. A phenotype microarray analysis was used to identify further conditions for A-PG function.