Organophosphate hydrolase interacts with Ton components and is targeted to the membrane only in the presence of the ExbB/ExbD complex

Abstract

Our study aims to investigate the physiological role of organophosphate hydrolase (OPH), hitherto known for its involvement in the degradation of organophosphate insecticides and nerve agents in Sphingobium fuliginis. We find that OPH exists as part of the TonB‐dependent Transport system that is involved in nutrient transport across the bacterial outer membrane. OPH interacts physically with the Ton complex components ExbD and TonB. The surface‐exposed arginine residues (R91 and R96) of OPH facilitate its interaction with ExbD. OPH is targeted to the inner membrane of Escherichia coli only when it is co‐expressed with either ExbD or the ExbB/ExbD complex. In the absence of ExbD, OPH remains in the cytoplasm. Our findings suggest a role for OPH in outer membrane transport.

TonB-Dependent Transporters in Sphingomonads: Unraveling Their Distribution and Function in Environmental Adaptation

“…Interestingly, the TonB complex components were co-purified along with PTE. PTE are shown to interact physically with TonB complex components ExbB/ExbD and TonB, showing the existence of a unique four-component TonB complex in S. fuliginis [31]. Co-purification of TonB complex components along with PTE and the inability of pte null mutants of Sphingopyxis wildii to grow in a medium with OP insecticide methyl parathion as a source of phosphate suggest the involvement of a novel TonB-dependent transport system in transport of OP insecticides.…”

Immune responses and protective efficacy of outer membrane protein ExbB of Pseudomonas fluorescens against Aeromonas hydrophila and Pseudomonas fluorescens affecting Carassius auratus

“…The ExbB outer membrane protein of bacteria is in the outermost layer of the cell membrane, participates in material transport and energy metabolism (Celia et al 2019;Gudla et al 2019), may interact with the host (Liao et al 2015), and has immune activity. In the present study, P. fluorescens ExbB was obtained by molecular cloning, and the optimal expressing conditions for OmpA were the strain OD 600 of 1.0, IPTG concentration of 0.3 mmol/L, induction temperature of 32 °C, and time of 3 h. In addition, purified ExbB was obtained with Ni-NTA flow resin.…”

“…Previous studies have shown that outer membrane proteins A, C, F, and H have a better antigenicity and immunogenicity, activating the immune functions of animals (De Mot et al 1994;Pore and Chakrabarti 2013;Lee et al 2005;Diao et al 2020), and improved the resistance of animals to bacterial infection, having prospective applications in protein subunit vaccines. The outer membrane protein ExbB located in the outermost layer of bacteria was five copies pentamer, which can around a dimer of ExbD and form TonB-ExbB-ExbD protein complex to promote the absorption of essential nutrients and energy harvesting (Pramanik et al 2011;Celia et al 2019;Gudla et al 2019). However, there is no report about the immune responses and protective efficacy of P. fluorescens ExbB.…”