title: Enzymatic analysis of the effect of naturally occurring Leu138Pro mutation identified in SHV β-lactamase on hydrolysis of penicillin and ampicillin.
abstract: BACKGROUND
  The aim of this study was to analyze the significance of leucine to proline substitution at position 138(Leu138Pro) on the hydrolysis of penicillin and ampicillin that we identified in the blaSHV gene of clinical Escherichia coli swine isolate.
  
  
  RESULTS
  Kinetic analysis of the mutant proteins showed that K(m) value of the purified L138P mutant was comparatively higher than SHV-1, SHV-33 and SHV-33(L138P) enzyme for penicillin and ampicillin. Docking simulation of the SHV-1 and SHV-(L138P) enzymes also confirmed that β-lactamases preferred penicillin to ampicillin and the SHV-1 had a higher binding affinity for antibiotics compared to the SHV-(L138P) and other mutants.
  
  
  CONCLUSIONS
  Our result demonstrated that L138P has a reduced role in penicillin and ampicillin hydrolyzing properties of SHV β-lactamases. These naturally occurring mutations rendering reduced function of the existing protein could trigger the emergence or acquisition of more effective alternative mechanisms for β-lactam hydrolysis.
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Brain Korea 21 for Veterinary Science, Seoul National University, Seoul, S Korea.
authors.forename: Nabin
authors.initials: N
authors.lastname: Rayamajhi
authors.forename: Jeong Chan
authors.initials: JC
authors.lastname: Joo
authors.forename: Seung Bin
authors.initials: SB
authors.lastname: Cha
authors.forename: Subarna
authors.initials: S
authors.lastname: Pokherl
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Shin
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Yoo
authors.forename: Han Sang
authors.initials: HS
authors.lastname: Yoo
mesh_terms: D019943:Amino Acid Substitution; D000667:Ampicillin / Q000378:metabolism*; D003001:Cloning, Molecular; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics*; D006868:Hydrolysis; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010406:Penicillins / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D010406:Penicillins; D000667:Ampicillin; D001618:beta-Lactamases