TY - JOUR
T1 - Tellurite-mediated damage to the Escherichia coli NDH-dehydrogenases and terminal oxidases in aerobic conditions
AU - Díaz-Vásquez, Waldo A.
AU - Abarca-Lagunas, María J.
AU - Cornejo, Fabián A.
AU - Pinto, Camilo A.
AU - Arenas, Felipe A.
AU - Vásquez, Claudio C.
N1 - Publisher Copyright:
© 2014 Elsevier Inc. All rights reserved.
PY - 2015/1/15
Y1 - 2015/1/15
N2 - Escherichia coli exposed to tellurite shows augmented membrane lipid peroxidation and ROS content. Also, reduced thiols, protein carbonylation, [Fe-S] center dismantling, and accumulation of key metabolites occur in these bacteria. In spite of this, not much is known about tellurite effects on the E. coli electron transport chain (ETC). In this work, tellurite-mediated damage to the E. coli ETC's NADH dehydrogenases and terminal oxidases was assessed. Mutant lacking ETC components showed delayed growth, decreased oxygen consumption and increased ROS in the presence of the toxicant. Membranes from tellurite-exposed E. coli exhibited decreased oxygen consumption and dNADH/NADH dehydrogenase activity, showing an impairment of NDH-I but not of NDH-II activity. Regarding terminal oxidases, only the bo oxidase complex was affected by tellurite. When assaying NDH-I and NDH-II activity in the presence of superoxide, the NDH-I complex was preferentially damaged. The activity was partly restored in the presence of reducing agents, sulfide and Fe2+ under anaerobic conditions, suggesting that damage affects NDH-I [4Fe-4S] centers. Finally, augmented membrane protein oxidation along with reduced oxidase activity was observed in the presence of the toxicant. Also, the increased expression of genes encoding alternative terminal oxidases probably reflects a cell's change towards anaerobic respiration when facing tellurite.
AB - Escherichia coli exposed to tellurite shows augmented membrane lipid peroxidation and ROS content. Also, reduced thiols, protein carbonylation, [Fe-S] center dismantling, and accumulation of key metabolites occur in these bacteria. In spite of this, not much is known about tellurite effects on the E. coli electron transport chain (ETC). In this work, tellurite-mediated damage to the E. coli ETC's NADH dehydrogenases and terminal oxidases was assessed. Mutant lacking ETC components showed delayed growth, decreased oxygen consumption and increased ROS in the presence of the toxicant. Membranes from tellurite-exposed E. coli exhibited decreased oxygen consumption and dNADH/NADH dehydrogenase activity, showing an impairment of NDH-I but not of NDH-II activity. Regarding terminal oxidases, only the bo oxidase complex was affected by tellurite. When assaying NDH-I and NDH-II activity in the presence of superoxide, the NDH-I complex was preferentially damaged. The activity was partly restored in the presence of reducing agents, sulfide and Fe2+ under anaerobic conditions, suggesting that damage affects NDH-I [4Fe-4S] centers. Finally, augmented membrane protein oxidation along with reduced oxidase activity was observed in the presence of the toxicant. Also, the increased expression of genes encoding alternative terminal oxidases probably reflects a cell's change towards anaerobic respiration when facing tellurite.
KW - Bacterial metabolism
KW - E. coli
KW - Electron transport chain
KW - Enzyme inactivation
KW - Membrane protein
KW - NADH
KW - NADH:ubiquinone oxidoreductase I
KW - Oxidative damage
KW - Tellurite
KW - Terminal oxidase
UR - http://www.scopus.com/inward/record.url?scp=84920059630&partnerID=8YFLogxK
U2 - 10.1016/j.abb.2014.10.011
DO - 10.1016/j.abb.2014.10.011
M3 - Article
C2 - 25447814
AN - SCOPUS:84920059630
SN - 0003-9861
VL - 566
SP - 67
EP - 75
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
ER -