The solution structure of the bacterial HSP70 chaperone protein domain DnaK(393-507) in complex with the peptide NRLLLTG.
The Hsp70 family of molecular chaperones participates in a number of cellular processes, including binding to nascent polypeptide chains and assistance in protein (re)folding and degradation. We present the solution structure of the substrate binding domain (residues 393-507) of the Escherichia coli Hsp70, DnaK, that is bound to the peptide NRLLLTG and compare it to the crystal structure of DnaK(389-607) bound to the same peptide. The construct discussed here does not contain the alpha-helical domain that characterizes earlier published peptide-bound structures of the Hsp70s. It is established that removing the alpha-helical domain in its entirety does not affect the primary interactions or structure of the DnaK(393-507) in complex with the peptide NRLLLTG. In particular, the arch that protects the substrate-binding cleft is also formed in the absence of the helical lid. 15N-relaxation measurements show that the peptide-bound form of DnaK(393-507) is relatively rigid. As compared to the peptide-free state, the peptide-bound state of the domain shows distinct, widespread, and contiguous differences in structure extending toward areas previously defined as important to the allosteric regulation of the Hsp70 chaperones.
Biophysics Research Division, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
Shawn Y
SY
Stevens
Sheng
S
Cai
Maurizio
M
Pellecchia
Erik R P
ER
Zuiderweg
D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012996:Solutions
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D009842:Oligopeptides; D012996:Solutions; C063842:dnaK protein, E coli