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Structure and functional properties of the Bacillus subtilis transcriptional repressor Rex.

Wang, Ellen LU ; Bauer, Mikael LU ; Rogstam, Annika LU ; Linse, Sara LU ; Logan, Derek LU and von Wachenfeldt, Claes LU (2008) In Molecular Microbiology 69(2). p.466-478
Abstract
The transcription factor Rex has been implicated in regulation of the expression of genes important for fermentative growth and for growth under conditions of low oxygen tension in several Gram-positive bacteria. Rex senses the redox poise of the cell through changes in the NADH/NAD(+) ratio. The crystal structures of two essentially identical Rex proteins, from Thermus aquaticus and T. thermophilus, have previously been determined in complex with NADH. Here we present the crystal structure of the Rex protein from Bacillus subtilis, as well as extensive studies of its affinity for nucleotides and DNA, using surface plasmon resonance, isothermal titration calorimetry and electrophoretic mobility shift assays. We show that Rex has a very... (More)
The transcription factor Rex has been implicated in regulation of the expression of genes important for fermentative growth and for growth under conditions of low oxygen tension in several Gram-positive bacteria. Rex senses the redox poise of the cell through changes in the NADH/NAD(+) ratio. The crystal structures of two essentially identical Rex proteins, from Thermus aquaticus and T. thermophilus, have previously been determined in complex with NADH. Here we present the crystal structure of the Rex protein from Bacillus subtilis, as well as extensive studies of its affinity for nucleotides and DNA, using surface plasmon resonance, isothermal titration calorimetry and electrophoretic mobility shift assays. We show that Rex has a very high affinity for NADH but that its affinity for NAD(+) is 20 000 times lower. However the NAD(+) affinity is increased by a factor of 30 upon DNA binding, suggesting that there is a positive allosteric coupling between DNA binding and NAD(+) binding. The crystal structures of two pseudo-apo forms (from crystals soaked with NADH and co-crystallized with ATP) show a very different conformation from the previously determined Rex:NADH complexes, in which the N-terminal domains are splayed away from the dimer core. A mechanism is proposed whereby conformational changes in a C-terminal domain-swapped helix mediate the transition from a flexible DNA-binding form to a locked NADH-bound form incapable of binding DNA. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Molecular Microbiology
volume
69
issue
2
pages
466 - 478
publisher
Wiley-Blackwell
external identifiers
  • wos:000257569200014
  • scopus:47249112605
ISSN
1365-2958
DOI
10.1111/j.1365-2958.2008.06295.x
language
English
LU publication?
yes
id
052488b5-9d2f-4c3e-9e66-6bcdc47d4fb4 (old id 1154037)
date added to LUP
2008-10-10 12:49:24
date last changed
2017-08-27 03:46:53
@article{052488b5-9d2f-4c3e-9e66-6bcdc47d4fb4,
  abstract     = {The transcription factor Rex has been implicated in regulation of the expression of genes important for fermentative growth and for growth under conditions of low oxygen tension in several Gram-positive bacteria. Rex senses the redox poise of the cell through changes in the NADH/NAD(+) ratio. The crystal structures of two essentially identical Rex proteins, from Thermus aquaticus and T. thermophilus, have previously been determined in complex with NADH. Here we present the crystal structure of the Rex protein from Bacillus subtilis, as well as extensive studies of its affinity for nucleotides and DNA, using surface plasmon resonance, isothermal titration calorimetry and electrophoretic mobility shift assays. We show that Rex has a very high affinity for NADH but that its affinity for NAD(+) is 20 000 times lower. However the NAD(+) affinity is increased by a factor of 30 upon DNA binding, suggesting that there is a positive allosteric coupling between DNA binding and NAD(+) binding. The crystal structures of two pseudo-apo forms (from crystals soaked with NADH and co-crystallized with ATP) show a very different conformation from the previously determined Rex:NADH complexes, in which the N-terminal domains are splayed away from the dimer core. A mechanism is proposed whereby conformational changes in a C-terminal domain-swapped helix mediate the transition from a flexible DNA-binding form to a locked NADH-bound form incapable of binding DNA.},
  author       = {Wang, Ellen and Bauer, Mikael and Rogstam, Annika and Linse, Sara and Logan, Derek and von Wachenfeldt, Claes},
  issn         = {1365-2958},
  language     = {eng},
  number       = {2},
  pages        = {466--478},
  publisher    = {Wiley-Blackwell},
  series       = {Molecular Microbiology},
  title        = {Structure and functional properties of the Bacillus subtilis transcriptional repressor Rex.},
  url          = {http://dx.doi.org/10.1111/j.1365-2958.2008.06295.x},
  volume       = {69},
  year         = {2008},
}