Characterization of the Escherichia coli YedU protein as a molecular chaperone.
We have cloned, purified to homogeneity, and characterized as a molecular chaperone the Escherichia coli YedU protein. The purified protein shows a single band at 31 kDa on SDS-polyacrylamide gels and forms dimers in solution. Like other chaperones, YedU interacts with unfolded and denatured proteins. It promotes the functional folding of citrate synthase and alpha-glucosidase after urea denaturation and prevents the aggregation of citrate synthase under heat shock conditions. YedU forms complexes with the permanently unfolded protein, reduced carboxymethyl alpha-lactalbumin. In contrast to DnaK/Hsp70, ATP does not stimulate YedU-dependent citrate synthase renaturation and does not affect the interaction between YedU and unfolded proteins, and YedU does not display any peptide-stimulated ATPase activity. We conclude that YedU is a novel chaperone which functions independently of an ATP/ADP cycle.
Malki
Abderrahim
A
Stress molecules, Institut Jacques Monod, Université Paris 7, 2 place Jussieu, 75005 Paris, France.
Kern
Renée
R
Abdallah
Jad
J
Richarme
Gilbert
G
D000818:Animals; D002950:Citrate (si)-Synthase / Q000737:chemistry / Q000378:metabolism; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D007768:Lactalbumin / Q000737:chemistry / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011489:Protein Denaturation; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C469996:hchA protein, E coli; D007768:Lactalbumin; D000242:Cyclic AMP; D002950:Citrate (si)-Synthase; D000520:alpha-Glucosidases; C063842:dnaK protein, E coli