Journal of Thermodynamics & Catalysis
Open Access
ISSN: 2157-7544
+44 1300 500008
ISSN: 2157-7544
+44 1300 500008
Edward Wright
Tanzania
Research Article
Effects of Proton Linkage on Thermodynamic Properties of Enzyme-Antibiotic Complexes of the Aminoglycoside Nucleotidyltransferase (2³)-Ia
Author(s): Edward Wright and Engin H. SerpersuEdward Wright and Engin H. Serpersu
Aminoglycoside nucleotidyltransferase(2″)-Ia (ANT) catalyzes the covalent modification of certain aminoglycoside antibiotics and imparts resistance to bacteria which possess this enzyme. Isothermal titration calorimetry (ITC) experiments using two structurally similar substrates (kanamycin A and kanamycin B) and a structurally different inhibitor (neomycin) were performed to determine pH and proton linkage effects on thermodynamic properties of enzyme–aminoglycoside complexes. Data showed that there was a decrease in pKa for one or more carboxyl groups on the enzyme that interacts with 2′-amino group of neomycin or kanamycin B. Protonation state of this site exerted a significant effect on the binding affinity of ligand to ANT. ITC experiments also showed that the loss of affinity at higher pH values was not as pronounced for neomycin com.. View More»
DOI:
10.4172/2157-7544.1000105