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Role of histidines in the binding of violaxanthin de-epoxidase to the thylakoid membrane as studied by site-directed mutagenesis

Gisselsson, A; Szilagyi, Anna LU and Åkerlund, Hans-Erik LU (2004) In Physiologia Plantarum 122(3). p.337-343
Abstract
Regulation of violaxanthin de-epoxidase (VDE) involves a conformational change at low lumenal pH, followed by binding of the enzyme to the thylakoid membrane. The role of histidine residues in this process was studied by release of unbound enzyme from thylakoids upon sonication, on a pH scale from 4.7 to 7.1. The co-operativity for binding of spinach VDE (four histidines) to the membrane was found to be 3.8, with respect to protons, and had an inflexion point at pH 6.6, whereas VDE from wheat (three histidines) showed a co-operativity of 2.9 and had an inflexion point at pH 6.2. Mutant forms of VDE were constructed and probed for their binding to the outside of thylakoid membranes. With one or two histidines substituted for alanine or... (More)
Regulation of violaxanthin de-epoxidase (VDE) involves a conformational change at low lumenal pH, followed by binding of the enzyme to the thylakoid membrane. The role of histidine residues in this process was studied by release of unbound enzyme from thylakoids upon sonication, on a pH scale from 4.7 to 7.1. The co-operativity for binding of spinach VDE (four histidines) to the membrane was found to be 3.8, with respect to protons, and had an inflexion point at pH 6.6, whereas VDE from wheat (three histidines) showed a co-operativity of 2.9 and had an inflexion point at pH 6.2. Mutant forms of VDE were constructed and probed for their binding to the outside of thylakoid membranes. With one or two histidines substituted for alanine or arginine, a lower co-operativity (1.6-2.3) was found, compared with the wild type. Based on these findings, and that the pKa value for histidine is within the range where the VDE binding takes place, we propose that protonation of the histidine residues at low pH induces the conformational change of VDE, and hence indirectly regulates binding of the enzyme to the thylakoid membrane. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physiologia Plantarum
volume
122
issue
3
pages
337 - 343
publisher
Wiley Online Library
external identifiers
  • wos:000224442700006
  • scopus:7444220226
ISSN
0031-9317
DOI
10.1111/j.1399-3054.2004.00415.x
language
English
LU publication?
yes
id
73f169fe-0c55-4a5b-8a1e-1a0037b18c36 (old id 138564)
date added to LUP
2007-07-04 17:08:30
date last changed
2017-01-01 07:23:23
@article{73f169fe-0c55-4a5b-8a1e-1a0037b18c36,
  abstract     = {Regulation of violaxanthin de-epoxidase (VDE) involves a conformational change at low lumenal pH, followed by binding of the enzyme to the thylakoid membrane. The role of histidine residues in this process was studied by release of unbound enzyme from thylakoids upon sonication, on a pH scale from 4.7 to 7.1. The co-operativity for binding of spinach VDE (four histidines) to the membrane was found to be 3.8, with respect to protons, and had an inflexion point at pH 6.6, whereas VDE from wheat (three histidines) showed a co-operativity of 2.9 and had an inflexion point at pH 6.2. Mutant forms of VDE were constructed and probed for their binding to the outside of thylakoid membranes. With one or two histidines substituted for alanine or arginine, a lower co-operativity (1.6-2.3) was found, compared with the wild type. Based on these findings, and that the pKa value for histidine is within the range where the VDE binding takes place, we propose that protonation of the histidine residues at low pH induces the conformational change of VDE, and hence indirectly regulates binding of the enzyme to the thylakoid membrane.},
  author       = {Gisselsson, A and Szilagyi, Anna and Åkerlund, Hans-Erik},
  issn         = {0031-9317},
  language     = {eng},
  number       = {3},
  pages        = {337--343},
  publisher    = {Wiley Online Library},
  series       = {Physiologia Plantarum},
  title        = {Role of histidines in the binding of violaxanthin de-epoxidase to the thylakoid membrane as studied by site-directed mutagenesis},
  url          = {http://dx.doi.org/10.1111/j.1399-3054.2004.00415.x},
  volume       = {122},
  year         = {2004},
}