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Substitution of conserved methionines by leucines in chloroplast small heat shock protein results in loss of redox-response but retained chaperone-like activity

Gustavsson, Niklas LU ; Kokke, Bas P A; Anzelius, Björn LU ; Boelens, Wilbert C and Sundby, Cecilia (2001) In Protein Science 10(9). p.1785-1793
Abstract
During evolution of land plants, a specific motif occurred in the N-terminal domain of the chloroplast-localized small heat shock protein, Hsp21: a sequence with highly conserved methionines, which is predicted to form an amphipathic -helix with the methionines situated along one side. The functional role of these conserved methionines is not understood. We have found previously that treatment, which causes methionine sulfoxidation in Hsp21, also leads to structural changes and loss of chaperone-like activity. Here, mutants of Arabidopsis thaliana Hsp21 protein were created by site-directed mutagenesis, whereby conserved methionines were substituted by oxidation-resistant leucines. Mutants lacking the only cysteine in Hsp21 were also... (More)
During evolution of land plants, a specific motif occurred in the N-terminal domain of the chloroplast-localized small heat shock protein, Hsp21: a sequence with highly conserved methionines, which is predicted to form an amphipathic -helix with the methionines situated along one side. The functional role of these conserved methionines is not understood. We have found previously that treatment, which causes methionine sulfoxidation in Hsp21, also leads to structural changes and loss of chaperone-like activity. Here, mutants of Arabidopsis thaliana Hsp21 protein were created by site-directed mutagenesis, whereby conserved methionines were substituted by oxidation-resistant leucines. Mutants lacking the only cysteine in Hsp21 were also created. Protein analyses by nondenaturing electrophoresis, size exclusion chromatography, and circular dichroism proved that sulfoxidation of the four highly conserved methionines (M49, M52, M55, and M59) is responsible for the oxidation-induced conformational changes in the Hsp21 oligomer. In contrast, the chaperone-like activity was not ultimately dependent on the methionines, because it was retained after methionine-to-leucine substitution. The functional role of the conserved methionines in Hsp21 may be to offer a possibility for redox control of chaperone-like activity and oligomeric structure dynamics. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
Chaperone-like activity, methionine sulfoxidation, redox-response, small heat shock protein
in
Protein Science
volume
10
issue
9
pages
1785 - 1793
publisher
The Protein Society
external identifiers
  • scopus:0034841455
ISSN
1469-896X
language
English
LU publication?
yes
id
28a73216-cb79-4da4-9c2e-f0213dfb2b2d (old id 124984)
alternative location
http://www.proteinscience.org/cgi/content/full/10/9/1785
date added to LUP
2007-07-05 10:54:14
date last changed
2018-01-07 05:54:06
@article{28a73216-cb79-4da4-9c2e-f0213dfb2b2d,
  abstract     = {During evolution of land plants, a specific motif occurred in the N-terminal domain of the chloroplast-localized small heat shock protein, Hsp21: a sequence with highly conserved methionines, which is predicted to form an amphipathic -helix with the methionines situated along one side. The functional role of these conserved methionines is not understood. We have found previously that treatment, which causes methionine sulfoxidation in Hsp21, also leads to structural changes and loss of chaperone-like activity. Here, mutants of Arabidopsis thaliana Hsp21 protein were created by site-directed mutagenesis, whereby conserved methionines were substituted by oxidation-resistant leucines. Mutants lacking the only cysteine in Hsp21 were also created. Protein analyses by nondenaturing electrophoresis, size exclusion chromatography, and circular dichroism proved that sulfoxidation of the four highly conserved methionines (M49, M52, M55, and M59) is responsible for the oxidation-induced conformational changes in the Hsp21 oligomer. In contrast, the chaperone-like activity was not ultimately dependent on the methionines, because it was retained after methionine-to-leucine substitution. The functional role of the conserved methionines in Hsp21 may be to offer a possibility for redox control of chaperone-like activity and oligomeric structure dynamics.},
  author       = {Gustavsson, Niklas and Kokke, Bas P A and Anzelius, Björn and Boelens, Wilbert C and Sundby, Cecilia},
  issn         = {1469-896X},
  keyword      = {Chaperone-like activity,methionine sulfoxidation,redox-response,small heat shock protein},
  language     = {eng},
  number       = {9},
  pages        = {1785--1793},
  publisher    = {The Protein Society},
  series       = {Protein Science},
  title        = {Substitution of conserved methionines by leucines in chloroplast small heat shock protein results in loss of redox-response but retained chaperone-like activity},
  volume       = {10},
  year         = {2001},
}