INVESTIGADORES
CHECA Susana Karina
artículos
Título:
A single serine residue determines selectivity to monovalent metal ions in metalloregulators of the MerR family
Autor/es:
IBAÑEZ, MARIA MARTA; CHECA, SUSANA K. (CORR. AUTHOR); SONCINI, FERNANDO C. (CORR. AUTHOR)
Revista:
JOURNAL OF BACTERIOLOGY
Editorial:
AMER SOC MICROBIOLOGY
Referencias:
Lugar: Washington; Año: 2015 vol. 197 p. 1606 - 1613
ISSN:
0021-9193
Resumen:
IMPORTANTE: CHECA SK y SONCINI SON AUTORES DE CORRESPONDENCIA DE ESTA PUBLICACIÓN - Calification SCImago-Q1, IF(2014): 2,808, 5-YEAR IMPACT FACTOR: 3.298. [Selected by the Editors of the Journal for the Articles of Significant Interest Section (Design of a Broad-Specificity MerR-Metal Sensor by a Single Amino Acid Substitutions. DOI: 10.1128/JB.00165-15)]. MerR metalloregulators alleviate toxicity caused by the excess of metal ions such copper, zinc, mercury, lead, cadmium, silver or gold by triggering the expression of specific efflux or detoxification systems upon metal detection. The sensor protein binds the inducer metal ion using two conserved cysteine residues at the C-terminal metal-binding loop (MBL). Divalent metal ions sensors such as MerR and ZntR require a third cysteine residue located at the beginning of the dimerization (alpha-5) helix for metal coordination, while monovalent metal ions sensors such as CueR and GolS have a serine residue at this position. This serine residue was proposed to provide hydrophobic and steric restrictions to privilege the binding of monovalent metal ions. Here, we show that the presence of alanine at this position does not modify the activation pattern of monovalent metal sensors. In contrast, GolS or CueR mutant sensors with a substitution of the serine residue by cysteine respond to monovalent metal ions or Hg(II) with high sensitivity. Furthermore, in a mutant deleted of the Zn(II) exporter ZntA they also trigger the expression of their target genes in response to either Zn(II), Cd(II), Pb(II), or Co(II).