title: Transient association of newly synthesized unfolded proteins with the heat-shock GroEL protein.
abstract: It has been suggested that newly synthesized proteins are maintained in their unfolded state by cellular ATP-driven factors which may prevent or reverse the formation of misfolded structures or promote the correct assembly of oligomeric proteins or post-translational secretion. Using a photocross-linking approach, we have identified the 20S heat-shock GroEL protein as the major cytosolic component which forms a complex with the unfolded newly synthesized pre-beta-lactamase or chloramphenicol acetyltransferase in Escherichia coli. Dissociation of these complexes is ATP-dependent. The unfolded state of pre-beta-lactamase, maintained by the transient interaction with GroEL, may be essential for the secretion of this protein.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000345:Affinity Labels; D001426:Bacterial Proteins / Q000378:metabolism*; D018834:Chaperonin 60; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004220:Disulfides / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D010777:Photochemistry; D010957:Plasmids; D014176:Protein Biosynthesis; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D001426:Bacterial Proteins; D018834:Chaperonin 60; D003432:Cross-Linking Reagents; D004220:Disulfides; D004792:Enzyme Precursors; D006360:Heat-Shock Proteins; D000255:Adenosine Triphosphate; D015500:Chloramphenicol O-Acetyltransferase; D001618:beta-Lactamases; D004229:Dithiothreitol