PMID:15849180
| Citation |
Shi, YY, Hong, XG and Wang, CC (2005) The C-terminal (331-376) sequence of Escherichia coli DnaJ is essential for dimerization and chaperone activity: a small angle X-ray scattering study in solution. J. Biol. Chem. 280:22761-8 |
|---|---|
| Abstract |
DnaJ, an Escherichia coli Hsp40 protein composed of 376 amino acid residues, is a chaperone with thioldisulfide oxidoreductase activity. We present here for the first time a small angle x-ray scattering study of intact DnaJ and a truncated version, DnaJ (1-330), in solution. The molecular weight of DnaJ and DnaJ (1-330) determined by both small angle x-ray scattering and size-exclusion chromatography provide direct evidence that DnaJ is a homodimer and DnaJ (1-330) is a monomer. The restored models show that DnaJ is a distorted omega-shaped dimeric molecule with the C terminus of each subunit forming the central part of the omega, whereas DnaJ (1-330) exists as a monomer. This indicates that the deletion of the C-terminal 46 residues of DnaJ impairs the association sites, although it does not cause significant conformational changes. Biochemical studies reveal that DnaJ (1-330), while fully retaining its thiol-disulfide oxidoreductase activity, is structurally less stable, and its peptide binding capacity is severely impaired relative to that of the intact molecule. Together, our results reveal that the C-terminal (331-376) residues are directly involved in dimerization, and the dimeric structure of DnaJ is necessary for its chaperone activity but not required for the thiol-disulfide oxidoreductase activity. |
| Links |
PubMed Online version:10.1074/jbc.M503643200 |
| Keywords |
Chromatography; Dimerization; Disulfides; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Escherichia coli/metabolism; Escherichia coli Proteins; HSP40 Heat-Shock Proteins; Heat-Shock Proteins/chemistry; Heat-Shock Proteins/metabolism; Kinetics; Models, Molecular; Models, Statistical; Molecular Chaperones/chemistry; Oxidoreductases/chemistry; Protein Conformation; Protein Structure, Tertiary; Scattering, Radiation; Sulfhydryl Compounds/chemistry; X-Rays; Zinc Fingers |
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