Novel Tripartite Aromatic Acid Transporter Essential for Terephthalate Uptake in Comamonas sp. Strain E6

• DOI: 10.1128/aem.01600-13
• Publication Date: 2013-08-03T05:06:27Z
• Authors: Masaru Hosaka; Naofumi Kamimura; Shotaro Toribami; Kosuke Mori; Daisuke Kasai; Masao Fukuda; Eiji Masai
• Keywords: Strain (injury); Comamonas

ABSTRACT It has been suggested that a novel type of aromatic acid transporter, which is similar to the tripartite tricarboxylate transporter (TTT), involved in terephthalate (TPA) uptake by Comamonas sp. strain E6. This suggestion was based on presence putative TPA-binding protein gene, tphC , TPA catabolic operon. The gene essential for growth and genes encoding TTT-like substrate-binding proteins. Here we identified two sets E6 genes, tctBA tpiBA encode cytoplasmic transmembrane Disruption tctA showed no influence but resulted complete loss citrate. suggests citrate uptake. On other hand, disruption tpiA or tpiB demonstrated both are Only when were introduced with into cells non-TPA-degrading Pseudomonas did resting transformant acquire ability convert TPA. From all these results, it concluded system consists TpiA-TpiB membrane components TphC. Interestingly, not only mutant unable grow isophthalate, also significant delays o -phthalate protocatechuate. These results able interact multiple constitutively transcribed as single operon cells, whereas transcription positively regulated TphR. completely inhibited protonophore, carbonyl cyanide m -chlorophenyl hydrazone, indicating requires proton motive force.