title: Substitution of the catalytic metal and protein PEGylation enhances activity and stability of bacterial phosphotriesterase.
abstract: Phosphotriesterase, a pesticide-degrading enzyme, from Flavobacterium sp. was cloned and expressed in Escherichia coli. The catalytic zinc ions were replaced by cobalt atoms increasing the catalytic activity of phosphotriesterase on different pesticides. This metal substitution increased the catalytic activity from 1.4 times to 4 times according to the pesticide. In order to explain this catalytic increase, QM/MM calculations were performed. Accordingly, the HOMO energy of the substrate is closer to the LUMO energy of the cobalt-substituted enzyme. The chemical modification of the enzyme surface with poly(ethylene glycol) increased the thermostability and stability against metal chelating agents of both metal phosphotriesterase preparations.
authors.affiliation: Instituto de Biotecnología, UNAM, Cuernavaca, Morelos, Mexico.
authors.forename: Lucia
authors.initials: L
authors.lastname: Perezgasga
authors.forename: Lorena
authors.initials: L
authors.lastname: Sánchez-Sánchez
authors.forename: Sergio
authors.initials: S
authors.lastname: Aguila
authors.forename: Rafael
authors.initials: R
authors.lastname: Vazquez-Duhalt
mesh_terms: D055162:Biocatalysis; D020134:Catalytic Domain; D002614:Chelating Agents / Q000737:chemistry; D003035:Cobalt; D004795:Enzyme Stability; D005417:Flavobacterium / Q000201:enzymology*; D008958:Models, Molecular; D044345:Phosphoric Triester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013696:Temperature; D015032:Zinc
chemical_list: D002614:Chelating Agents; D003035:Cobalt; D011092:Polyethylene Glycols; D044345:Phosphoric Triester Hydrolases; D015032:Zinc