6533b835fe1ef96bd129fe3e

RESEARCH PRODUCT

GroEL buffers against deleterious mutations

subject

description

GroEL, a heat-shock protein that acts as a molecular chaperone1, is overproduced in endosymbiotic but not in free-living bacteria2,3,4, presumably to assist in the folding of conformationally damaged proteins. Here we show that the overproduction of GroEL in Escherichia coli masks the effects of harmful mutations that have accumulated during a simulated process of vertical transmission. This molecular mechanism, which may be an adaptation to the bacterium's intracellular lifestyle, is able to rescue lineages from a progressive fitness decline resulting from the fixation of deleterious mutations under strong genetic drift5,6.