Structure and function of the molecular chaperone Trigger Factor.
Newly synthesized proteins often require the assistance of molecular chaperones to efficiently fold into functional three-dimensional structures. At first, ribosome-associated chaperones guide the initial folding steps and protect growing polypeptide chains from misfolding and aggregation. After that folding into the native structure may occur spontaneously or require support by additional chaperones which do not bind to the ribosome such as DnaK and GroEL. Here we review the current knowledge on the best-characterized ribosome-associated chaperone at present, the Escherichia coli Trigger Factor. We describe recent progress on structural and dynamic aspects of Trigger Factor's interactions with the ribosome and substrates and discuss how these interactions affect co-translational protein folding. In addition, we discuss the newly proposed ribosome-independent function of Trigger Factor as assembly factor of multi-subunit protein complexes. Finally, we cover the functional cooperation between Trigger Factor, DnaK and GroEL in folding of cytosolic proteins and the interplay between Trigger Factor and other ribosome-associated factors acting in enzymatic processing and translocation of nascent polypeptide chains.
Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany.
Anja
A
Hoffmann
Bernd
B
Bukau
Günter
G
Kramer
D018834:Chaperonin 60 / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry; D019696:Peptidylprolyl Isomerase / Q000378:metabolism*; D010641:Phenotype; D017510:Protein Folding; D021381:Protein Transport; D012270:Ribosomes / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010455:Peptides; C063842:dnaK protein, E coli; C403324:trigger factor, E coli; D019696:Peptidylprolyl Isomerase