Study of protein expression in Streptomyces sp. MC1 under Cr(VI) stress by two dimensional electrophoresis

ESTEVEZ, MC; BONILLA, JO; CALLEGARI, E; VILLEGAS LB

Mendoza

Encuentro; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Sociedad de Biología de Cuyo

In previous works, Streptomyces sp. MC1 has shown the capability to remove 98% of Cr(VI) (20mg L-1 of Cr(VI) as K2Cr2O7) in presence of 7.5mM of sulfate ions (as Na2SO4) in the culture media (MMm) during 48h of incubation, at 180 rpm and 30°C. The purpose of this study was to analyze the intracellular protein profile expressed by Streptomyces sp. MC1 in the presence or absence of the heavy metal using two-dimensional (2D) electrophoresis to identify proteins induced by Cr(VI) presence. Cells obtained at 48h in MMm in presence and absence of Cr(VI) were chilled in N2(l) and physically broken using mortar. The supernatants of cell lysate were used as protein samples. Intracellular proteins were concentrated by ultrafiltration using Vivaspin® 500 Centrifugal device. After 2D electrophoresis, differential spots (18) were identified, separated from gels and digested with trypsin. Tryptic peptides obtained were analyzed using nano-Ultra Performance Liquid Chromatography, coupled to tandem mass spectrometry. Bioinformatics analysis for protein identification was performed by searching against Swiss Protein database, using Mascot server and ProteoIQ v2.8. Proteins expressed only in the metal presence include proteins involved in protein biosynthesis (5), in oxide-reduction processes (1), proteins of response against stress (1), and one protein of resistance to the metalloid tellurium. Five spots appeared in both conditions and showed differences in spots intensity. These results indicate that nonspecific mechanisms of defense based on the overexpression of proteins capable to cope the metal presence were activated.