title: Organophosphate Hydrolase Is a Lipoprotein and Interacts with Pi-specific Transport System to Facilitate Growth of Brevundimonas diminuta Using OP Insecticide as Source of Phosphate.
abstract: Organophosphate hydrolase (OPH), encoded by the organophosphate degradation (opd) island, hydrolyzes the triester bond found in a variety of organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane ofBrevundimonas diminutain a pre-folded conformation by thetwinargininetransport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the pre-OPH in the cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of the ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pigenerated from organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consistent with this model,opdnull mutants ofB. diminutafailed to grow using the organophosphate insecticide methyl parathion as sole source of phosphate.
authors: From the Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, India and.
authors: Sunil
authors: S
authors: Parthasarathy
authors: From the Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, India and.
authors: Hari
authors: H
authors: Parapatla
authors: From the Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, India and.
authors: Aparna
authors: A
authors: Nandavaram
authors: the Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, United Kingdom.
authors: Tracy
authors: T
authors: Palmer
authors: From the Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, India and sdsl@uohyd.ernet.in.
authors: Dayananda
authors: D
authors: Siddavattam
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D042063:Caulobacteraceae / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D007306:Insecticides / Q000378:metabolism* / Q000494:pharmacology; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D007306:Insecticides; D008074:Lipoproteins; D028061:Phosphate Transport Proteins; C045290:phosphorylphosphatase; D010744:Phosphoric Monoester Hydrolases
keywords: biodegradation; lipoprotein secretion; multidrug transporter; protein complex; protein-protein interaction