Detection of a very rapid first phase in complex formation of DnaK and peptide substrate.
Complex formation of the Hsp70 chaperone DnaK with the fluorescence-labeled peptide ALLLSAPRR shows a very rapid first phase that has as yet not been observed with other peptides. This first phase is completed within the dead time (1-2 ms) of the stopped-flow instrument and corresponds to two thirds of the total increase in fluorescence. It occurs both in the presence and in the absence of ATP and is followed by a fast, a slow and a very slow step. These binding kinetics that are vastly different from those observed with other peptides might indicate the existence of a second substrate-binding site of DnaK.
Koller
Michael F
MF
Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Baici
Antonio
A
Huber
Michael
M
Christen
Philipp
P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D029968:Escherichia coli Proteins; D005453:Fluorescence; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D009842:Oligopeptides; D000255:Adenosine Triphosphate; C063842:dnaK protein, E coli