benK encodes a hydrophobic permease-like protein involved in benzoate degradation by Acinetobacter sp. strain ADP1

Abstract

The chromosomal benK gene was identified within a supraoperonic gene cluster involved in benzoate degradation by Acinetobacter sp. strain ADP1, and benK was expressed in response to a benzoate metabolite, cis,cis-muconate. The disruption of benK reduced benzoate uptake and impaired the use of benzoate or benzaldehyde as the carbon source. BenK was homologous to several aromatic compound transporters.

4-Chlorobenzoate Uptake in Comamonas sp. Strain DJ-12 Is Mediated by a Tripartite ATP-Independent Periplasmic Transporter

“…PcaK in Pseudomonas putida is characterized as a multifunctional transporter for 4-hydroxybenzoate as well as protocatechuate (22). Metabolic enzymes can accelerate the simple diffusion of the undissociated form of benzoate and 4-hydroxybenzoate across biological membranes (6,34).…”

“…Several transporters are known to facilitate the movement of aromatic compounds across the membrane: BenK for benzoate (6), OphD for phthalate (5), PcaK for 4-hydroxybenzoate and protocatechuate (22), TfdK for 2,4-dichlorophenoxyacetate (18), StyE for styrene (21), and XylN for m-xylene (15). However, little is known about the transporter for 4-chlorobenzoate (4CBA), which is a metabolite in the microbial breakdown of certain chloroaromatic pollutants.…”

“…Uptake of aromatic compounds is a prerequisite for metabolic degradation in microorganisms and can occur via passive diffusion of neutral compounds or active transport for charged compounds (6,12). Several transporters are known to facilitate the movement of aromatic compounds across the membrane: BenK for benzoate (6), OphD for phthalate (5), PcaK for 4-hydroxybenzoate and protocatechuate (22), TfdK for 2,4-dichlorophenoxyacetate (18), StyE for styrene (21), and XylN for m-xylene (15).…”

3-Chlorobenzoate is taken up by a chromosomally encoded transport system in Cupriavidus necator JMP134

“…Establishment and maintenance of concentration gradients requires the intracellular substrate concentration to be kept low relative to that of the external environment, which may be achieved by rapid transformation of the imported compound to metabolic intermediates (Harwood & Gibson, 1986;Merkel et al, 1989;Wong et al, 1994). In this case, uptake is effectively driven by the activity of catabolic enzymes, and this 'metabolic drag' mechanism (Wong et al, 1994) has been proposed for the uptake of benzoate (Harwood & Gibson, 1986) and 4-hydroxybenzoate (4-HB) (Merkel et al, 1989) in Rhodopseudomonas palustris, and for the uptake of 4-HB by Rhizobium leguminosarum (Wong et al, 1994).Transporter-mediated uptake has been reported for some non-chlorinated aromatic acids, such as benzoate (Collier et al, 1997;Thayer & Wheelis, 1982), 4-HB (Allende et al, 1993;Harwood et al, 1994), protocatechuate (Nichols & Harwood, 1997), mandelate (Higgins & Mandelstam, 1972), phenylacetate (Schleissner et al, 1994), 4-hydroxyphenylacetate (Prieto & García, 1997) and phthalate (Chang & Zylstra, 1999). Only a few of these permease-type transport proteins have been biochemically characterized, and the corresponding genes described.…”

“…Only a few of these permease-type transport proteins have been biochemically characterized, and the corresponding genes described. In most cases, identification of specific genes has been aided by the fact that candidate transport genes are located near to or within a gene cluster encoding the catabolic enzymes responsible for the degradation of aromatic compounds (Harwood et al, 1994;Collier et al, 1997;Chae & Zylstra, 2006).…”