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Conserved methionines in chloroplasts

Sundby, Cecilia; Harndahl, U; Gustavsson, N; Åhrman, Emma LU and Murphy, D J (2005) In Biochimica et Biophysica Acta - Proteins and Proteomics 1703(2). p.191-202
Abstract
Heat shock proteins counteract heat and oxidative stress. In chloroplasts, a small heat shock protein (Hsp21) contains a set of conserved methionines, which date back to early in the emergence of terrestrial plants. Methionines M49, M52, M55, M59, M62, M67 are located on one side of an amphipathic helix, which may fold back over two other conserved methionines (M97 and M101), to form a binding groove lined with methionines, for sequence-independent recognition of peptides with an overall hydrophobic character. The sHsps protect other proteins from aggregation by binding to their hydrophobic surfaces, which become exposed under stress. Data are presented showing that keeping the conserved methionines in Hsp21 in a reduced form is a... (More)
Heat shock proteins counteract heat and oxidative stress. In chloroplasts, a small heat shock protein (Hsp21) contains a set of conserved methionines, which date back to early in the emergence of terrestrial plants. Methionines M49, M52, M55, M59, M62, M67 are located on one side of an amphipathic helix, which may fold back over two other conserved methionines (M97 and M101), to form a binding groove lined with methionines, for sequence-independent recognition of peptides with an overall hydrophobic character. The sHsps protect other proteins from aggregation by binding to their hydrophobic surfaces, which become exposed under stress. Data are presented showing that keeping the conserved methionines in Hsp21 in a reduced form is a prerequisite to maintain such binding. The chloroplast generates reactive oxygen species under both stress and unstressed conditions, but this organelle is also a highly reducing cellular compartment. Chloroplasts contain a specialized isoform of the enzyme, peptide methionine sulfoxide reductase, the expression of which is light-induced. Recombinant proteins were used to measure that this reductase can restore Hsp21 methionines after sulfoxidation. This paper also describes how methionine sulfoxidation-reduction can be directly assessed by mass spectrometry, how methionine-to-leucine substitution affects Hsp21, and discusses the possible role for an Hsp21 methionine sulfoxidation-reduction cycle in quenching reactive oxygen species. (C) 2004 Elsevier B.V. All rights reserved. (Less)
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publication status
published
subject
in
Biochimica et Biophysica Acta - Proteins and Proteomics
volume
1703
issue
2
pages
191 - 202
publisher
Elsevier
external identifiers
  • wos:000227132100011
  • pmid:15680227
  • scopus:12844267505
ISSN
1570-9639
DOI
10.1016/j.bbapap.2004.09.001
language
English
LU publication?
yes
id
3c8fa584-39c8-4b8f-97df-8d8f5ca56b94 (old id 151474)
date added to LUP
2007-07-06 16:37:42
date last changed
2017-08-27 05:13:49
@article{3c8fa584-39c8-4b8f-97df-8d8f5ca56b94,
  abstract     = {Heat shock proteins counteract heat and oxidative stress. In chloroplasts, a small heat shock protein (Hsp21) contains a set of conserved methionines, which date back to early in the emergence of terrestrial plants. Methionines M49, M52, M55, M59, M62, M67 are located on one side of an amphipathic helix, which may fold back over two other conserved methionines (M97 and M101), to form a binding groove lined with methionines, for sequence-independent recognition of peptides with an overall hydrophobic character. The sHsps protect other proteins from aggregation by binding to their hydrophobic surfaces, which become exposed under stress. Data are presented showing that keeping the conserved methionines in Hsp21 in a reduced form is a prerequisite to maintain such binding. The chloroplast generates reactive oxygen species under both stress and unstressed conditions, but this organelle is also a highly reducing cellular compartment. Chloroplasts contain a specialized isoform of the enzyme, peptide methionine sulfoxide reductase, the expression of which is light-induced. Recombinant proteins were used to measure that this reductase can restore Hsp21 methionines after sulfoxidation. This paper also describes how methionine sulfoxidation-reduction can be directly assessed by mass spectrometry, how methionine-to-leucine substitution affects Hsp21, and discusses the possible role for an Hsp21 methionine sulfoxidation-reduction cycle in quenching reactive oxygen species. (C) 2004 Elsevier B.V. All rights reserved.},
  author       = {Sundby, Cecilia and Harndahl, U and Gustavsson, N and Åhrman, Emma and Murphy, D J},
  issn         = {1570-9639},
  language     = {eng},
  number       = {2},
  pages        = {191--202},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Proteins and Proteomics},
  title        = {Conserved methionines in chloroplasts},
  url          = {http://dx.doi.org/10.1016/j.bbapap.2004.09.001},
  volume       = {1703},
  year         = {2005},
}