A 10-kDa class-CI sHsp protects E. coli from oxidative and high-temperature stress

Planta. 2003 Sep;217(5):813-9. doi: 10.1007/s00425-003-1048-x. Epub 2003 May 13.

Abstract

We report on a new cDNA clone (Qshsp10.4-CI) of a Quercus suber L. class-CI small heat-shock protein (sHsp) obtained from cork (phellem), a highly oxidatively stressed plant tissue. The deduced gene product lacks the C-terminal extension and the consensus I region of the alpha-crystallin domain, being the most C-terminally truncated sHsp reported to date. In an attempt to prove that a protective function is possible for such a truncated sHsp, we overexpressed in Escherichia coli three recombinant sHsp-CIs, one (rQsHsp10.4-CI) showing the same truncation as Qshsp10.4-CI, a second (rN49) lacking the whole alpha-crystallin domain, and a third (rN153) consisting of a full-length sHsp-CI. The overexpression of rN153 and, remarkably, rQsHsp10.4-CI but not rN49 enhanced cell viability under high temperature and, interestingly, under oxidative stress. These results show that the C-terminal extension and the consensus I region of the alpha-crystallin domain are dispensable, but amino acids 1-41 of the alpha-crystallin domain (including the consensus II region) are essential for the protective activity of sHsp-CIs. On the other hand, two-dimensional immunodetection patterns showed accumulation of ca. 10-kDa sHsp-CI immunorelated polypeptides in cork and other oxidatively stressed tissues but not in control and heat-stressed tissues. We discuss the possible role of highly truncated sHsps in relation to oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Division / genetics
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Plant / chemistry
  • DNA, Plant / genetics
  • Electrophoresis, Gel, Two-Dimensional
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism
  • Heat-Shock Proteins / genetics*
  • Heat-Shock Proteins / metabolism
  • Hot Temperature
  • Immunoelectrophoresis, Two-Dimensional
  • Molecular Sequence Data
  • Oxidative Stress
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Quercus / genetics*
  • Quercus / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid

Substances

  • DNA, Complementary
  • DNA, Plant
  • Heat-Shock Proteins
  • Plant Proteins
  • Recombinant Fusion Proteins

Associated data

  • GENBANK/AJ243825
  • GENBANK/AJ584750