BACKGROUND: We have identified a novel class 1 integron (1503  bp), named In671 in a clinical @entity796 isolate. Integron sequence analysis revealed two gene cassettes, one coding for a new OXA-type b-lactamase designated as OXA-205 and the other coding for the aadB gene that is responsible for @entity5292 resistance. The 266 @entity3689 sequence of OXA-205 revealed that this b-lactamase belongs to the Ambler class D showing highest sequence homology to the OXA-2 sub-lineage. Our objective was to purify and characterize b-lactamase OXA-205. METHODS: @entity526 cells were transformed with a plasmid containing cloned bla OXA-205 gene from @entity796 . Purification of overproduced OXA-205 consisted of a single ion-exchange chromatography step. @entity214 -PAGE and isoelectric focusing were performed to determine the molecular mass and pI, respectively. Size-exclusion chromatography was undertaken to determine the OXA-205 oligomerization state. Substrate hydrolysis reactions were employed to assess enzyme kinetic parameters. RESULTS: Purification of OXA-205 yielded the enzyme with  >95  % purity (as verified by @entity214 -PAGE). Approximate yield of the protein was estimated to be 20  mg per liter of culture. OXA-205 had a pI at 8.1, molecular mass of 26  kDa and a monomeric native structure. Kinetic analysis revealed that OXA-205 hydrolyzed narrow spectrum substrates, including @entity869 , @entity7911 , @entity6101 , @entity3397 , @entity7048 and @entity2261 . Additionally, we observed a substrate inhibition profile towards @entity7911 and @entity6101 , but not with @entity869 or @entity3397 . Our results also show that OXA-205 conferred unusually high (among class D b-lactamases) resistance towards inhibition by @entity4202 . CONCLUSIONS: OXA-205 can be considered a narrow spectrum monomeric b-lactamase that demonstrates unusually high resistance profile towards inhibition by @entity4202 .

Purification and characterization of a new b-lactamase OXA-205 from XXXX .

@entity2261 :: ('MESH:D002444', 'Chemical') :: ['cefuroxime'] @entity7048 :: ('MESH:D002437', 'Chemical') :: ['cefazolin'] @entity796 :: ('287', 'Species') :: ['Pseudomonas aeruginosa', 'P. aeruginosa'] @entity7911 :: ('MESH:D002228', 'Chemical') :: ['carbenicillin'] @entity5292 :: ('D000617', 'Chemical') :: ['aminoglycoside'] @entity4202 :: ('D012965', 'Chemical') :: ['NaCl'] @entity6101 :: ('MESH:D010068', 'Chemical') :: ['oxacillin'] @entity3397 :: ('MESH:D010400', 'Chemical') :: ['penicillin G'] @entity214 :: ('CHEBI:8984', 'Chemical') :: ['SDS'] @entity869 :: ('MESH:D000667', 'Chemical') :: ['ampicillin'] @entity3689 :: ('D000596', 'Chemical') :: ['amino acid'] @entity526 :: ('562', 'Species') :: ['Escherichia coli']
@entity796 :: (287,Species) :: ['Pseudomonas aeruginosa']
