INVESTIGADORES
MORENO Diego Martin
artículos
Título:
Host-Specific Enzyme-Substrate Interactions in SPM-1 Metallo-ß-Lactamase are Modulated by Second Sphere Residues.
Autor/es:
LISANDRO J. GONZÁLEZ; DIEGO M. MORENO; ROBERT BONOMO; ALEJANDRO J. VILA
Revista:
PLOS PATHOGENS
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2014 vol. 10 p. 1 - 12
ISSN:
1553-7366
Resumen:
Pseudomonas aeruginosa is one of the most virulent and resistant non-fermenting Gram-negative pathogens in the clinic. Unfortunately, P. aeruginosa has acquired genes encoding metallo-β-lactamases (MβLs), enzymes able to hydrolyze most β-lactam antibiotics. SPM-1 is an MβL produced only by P. aeruginosa, while other MβLs are found in different bacteria. Despite similar active sites, the resistance profile of MβLs towards β-lactams changes from one enzyme to the other. SPM-1 is unique among pathogen-associated MβLs in that in that it contains ?atypical? second sphere residues (S84, G121). Codon randomization and selection of resistance-conferring mutants was performed. MICs, periplasmic enzymatic activity, western blots, Zn(II) requirements, and protein stability was assessed. The identity of second sphere residues modulates the substrate preferences and the resistance profile of SPM-1 expressed in P. aeruginosa. The second sphere residues found in wild type SPM-1 give rise to a substrate selectivity that is observed only in the periplasmic environment. By optimizing the catalytic efficiency, the enzyme stability and the Zn(II) binding features, molecular evolution meets the specific needs of a pathogenic bacterial host by means of subtle mutations outside the active site.