Journal Article

Zinc-<span class="smallCaps">l</span>-carnosine binds to molecular chaperone HSP70 and inhibits the chaperone activity of the protein

Asami Haga, Tomoya Okamoto, Shintaroh Yamada, Toshihiko Kubota, Ann Sanpei, Shota Takahashi, Masahiro Nakayama, Miki Nagai, Michiro Otaka, Toshio Miyazaki, Wataru Nunomura, Ewa Grave and Hideaki Itoh

in The Journal of Biochemistry

Published on behalf of The Japanese Biochemical Society

Volume 154, issue 3, pages 249-256
Published in print September 2013 | ISSN: 0021-924X
Published online May 2013 | e-ISSN: 1756-2651 | DOI: http://dx.doi.org/10.1093/jb/mvt041
Zinc-l-carnosine binds to molecular chaperone HSP70 and inhibits the chaperone activity of the protein

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In this study, we have investigated the specific binding proteins of Zinc-l-carnosine (Polaprezinc) using Polaprezinc-affinity column chromatography in vitro. A protein having a 70-kDa molecular mass was eluted by the linear gradient of 0–1.0 mM Polaprezinc from the affinity column and the protein was identified as the molecular chaperone HSP70 by immunoblotting. The chaperone activity of HSP70 was completely suppressed by Polaprezinc. The ATPase activity of HSP70 was affected to some extent by the reagent. In the circular dichroism (CD) spectrum, the secondary structure of HSP70 was changed in the presence of Polaprezinc, i.e. it decreased in the α-helix. We have determined the Polaprezinc-binding domain of HSP70 by using recombinant HSP70N- and C-domains. Although Polaprezinc could bind to both the N-terminal and the C-terminal of HSP70, the HSP70N-domain has a high affinity to the drug. Regarding the peptide cleavage of the HSP70N- and C-domains with proteinase K, the intact HSP70N still remained in the presence of Polaprezinc. On the other hand, the quantity of the intact C-domain slightly decreased under the same conditions along with the newly digested small peptides appeared. It has been suggested that Polaprezinc binds to HSP70 especially in the N-domains, suppresses the chaperone activity and delays an ATPase activities of HSP70.

Keywords: ATPase; chaperone activity; HSP70; molecular chaperone; zinc-l-carnosine

Journal Article.  4616 words.  Illustrated.

Subjects: Biochemistry

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