Abstract |
Seventy-kDa heat shock cognate protein (hsc70) and its homologs in bacteria, yeast and vertebrates are known to form complexes with S-carboxymethyl-alpha-lactalbumin (CMLA), an unfolded protein; and, this activity has been attributed to its C-terminal 30-kDa domain. Herein, we show that hsc70s isolated from the seeds of mung bean and peas, however, are not effective in complexing with CMLA, and that the 30-kDa domain of Arabidopsis hsc70 (At30) cannot form stable complexes with CMLA either. Moreover, chimeric 30-kDa domains, either composed of rat 18-kDa and Arabidopsis 10-kDa subdomains (R18At10) or with Arabidopsis 18-kDa and rat 10-kDa subdomains (At18R10), were prepared and tested for their ability to complex with CMLA or a heptapeptide FYQLALT. At18R10 cannot complex with both CMLA and FYQLALT. On the other hand, R18At10 is capable of forming complexes with FYQLALT at a level similar to that of the rat 30-kDa domain (R30). R18At10 also forms complexes with CMLA, but the amount of the R18At10/CMLA complexes is much less than that of R30/CMLA. The results imply that the 18-kDa subdomain dictates the binding specificity for heptapeptide, and that the C-terminal 10-kDa subdomain may also provide some selection or restriction for unfolded proteins to form complexes with hsc70.
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Authors | S J Wu, C Wang |
Journal | European journal of biochemistry
(Eur J Biochem)
Vol. 259
Issue 1-2
Pg. 449-55
(Jan 1999)
ISSN: 0014-2956 [Print] England |
PMID | 9914526
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Carrier Proteins
- HSC70 Heat-Shock Proteins
- HSP70 Heat-Shock Proteins
- Hspa8 protein, rat
- Oligopeptides
- Peptide Fragments
- Recombinant Fusion Proteins
- Lactalbumin
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Topics |
- Amino Acid Sequence
- Animals
- Arabidopsis
- Binding Sites
- Carrier Proteins
(genetics, metabolism)
- HSC70 Heat-Shock Proteins
- HSP70 Heat-Shock Proteins
(genetics, metabolism)
- Lactalbumin
(analogs & derivatives, metabolism)
- Molecular Sequence Data
- Oligopeptides
(metabolism)
- Peptide Fragments
(genetics, metabolism)
- Protein Binding
- Protein Conformation
- Rats
- Recombinant Fusion Proteins
(metabolism)
- Sequence Homology, Amino Acid
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