Identification and characterization of a carnitine transporter in Acinetobacter baumannii.
Identification and characterization of a carnitine transporter in Acinetobacter baumannii.
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DOI：
10.1002/mbo3.752
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发表时间：
2019-06
期刊：
影响因子：
3.4
通讯作者：
Averhoff B
中科院分区：
文献类型：
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作者：
Breisch J;Waclawska I;Averhoff B
机会性病原体鲍曼不动杆菌能够在肉碱上生长。编码肉毒碱降解为中间体苹果酸途径的基因是已知的，但介导肉毒碱吸收的转运蛋白仍有待鉴定。鲍曼不动杆菌的开放阅读框 HMPREF0010_01347 (aci01347) 被注释为编码甜菜碱/胆碱/肉碱转运蛋白 (BCCT) 家族潜在转运蛋白的基因。为了研究 Aci01347 的生理功能，从鲍曼不动杆菌 ATCC 19606 中删除了该基因。该突变体不再能够以肉碱作为唯一的碳和能源生长，这表明了该转运蛋白对于肉碱代谢的重要性。 Aci01347 在大肠杆菌 MKH13 中产生，该菌株缺乏任何相容的溶质转运蛋白，并且发现重组大肠杆菌 MKH13 菌株以能量依赖性方式吸收肉碱。 Aci01347 还转运胆碱，一种已知在渗透压下积累的化合物。胆碱转运与渗透压无关，这与渗透激活 BCCT 中不存在延长的 C 末端一致。我们认为 Aci01347 是肉碱转运蛋白，介导鲍曼不动杆菌依靠肉碱生长的第一步。
The opportunistic pathogen Acinetobacter baumannii is able to grow on carnitine. The genes encoding the pathway for carnitine degradation to the intermediate malic acid are known but the transporter mediating carnitine uptake remained to be identified. The open reading frame HMPREF0010_01347 (aci01347) of Acinetobacter baumannii is annotated as a gene encoding a potential transporter of the betaine/choline/carnitine transporter (BCCT) family. To study the physiological function of Aci01347, the gene was deleted from A. baumannii ATCC 19606. The mutant was no longer able to grow on carnitine as sole carbon and energy source demonstrating the importance of this transporter for carnitine metabolism. Aci01347 was produced in Escherichia coli MKH13, a strain devoid of any compatible solute transporter, and the recombinant E. coli MKH13 strain was found to take up carnitine in an energy‐dependent fashion. Aci01347 also transported choline, a compound known to be accumulated under osmotic stress. Choline transport was osmolarity‐independent which is consistent with the absence of an extended C‐terminus found in osmo‐activated BCCT. We propose that the Aci01347 is the carnitine transporter mediating the first step in the growth of A. baumannii on carnitine.