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Título:
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DnaK dependence of mutant ethanol oxidoreductases evolved for aerobic function and protective role of the chaperone against protein oxidative damage in Escherichia coli
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Autor/a:
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Echave Lozano, Pedro; Esparza-Cerón, M. Angel; Cabiscol Català, Elisa; Tamarit Sumalla, Jordi; Ros Salvador, Joaquim; Membrillo-Hernández, Jorge; Lin, Edmund C. C.
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Notas:
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The adhE gene of Escherichia coli encodes a multifunctional ethanol
oxidoreductase (AdhE) that catalyzes successive reductions of
acetyl-CoA to acetaldehyde and then to ethanol reversibly at the
expense of NADH. Mutant JE52, serially selected for acquired and
improved ability to grow aerobically on ethanol, synthesized an
AdhEA267T/E568K with two amino acid substitutions that sequentially
conferred improved catalytic properties and stability. Here
we show that the aerobic growth ability on ethanol depends also
on protection of the mutant AdhE against metal-catalyzed oxidation
by the chaperone DnaK (a member of the Hsp70 family). No
DnaK protection of the enzyme is evident during anaerobic growth
on glucose. Synthesis of DnaK also protected E. coli from H2O2
killing under conditions when functional AdhE is not required. Our
results therefore suggest that, in addition to the known role of
protecting cells against heat stress, DnaK also protects numerous
kinds of proteins from oxidative damage. |
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Derechos:
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(c) National Academy of Sciences, 2002
info:eu-repo/semantics/restrictedAccess |
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Tipo de documento:
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article
publishedVersion |
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Editor:
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National Academy of Sciences
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