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.
Stevens
Shawn Y
SY
Biophysics Research Division, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
Cai
Sheng
S
Pellecchia
Maurizio
M
Zuiderweg
Erik R P
ER
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