Homologue Structure of the SLAC1 Anion Channel for Closing Stomata in Leaves
The plant SLAC1 anion channel controls turgor pressure in the aperture-defining guard cells of plant stomata, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought or high levels of carbon dioxide. Here we determine the crystal structure of a bacterial homologue (Haemophilus influenzae) of SLAC1 at 1.20 {angstrom} resolution, and use structure-inspired mutagenesis to analyse the conductance properties of SLAC1 channels. SLAC1 is a symmetrical trimer composed from quasi-symmetrical subunits, each having ten transmembrane helices arranged from helical hairpin pairs to form a central five-helix transmembrane pore that is gated by an extremely conserved phenylalanine residue. Conformational features indicate a mechanism for control of gating by kinase activation, and electrostatic features of the pore coupled with electrophysiological characteristics indicate that selectivity among different anions is largely a function of the energetic cost of ion dehydration.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1041679
- Report Number(s):
- BNL-97357-2012-JA; NATUAS; TRN: US201212%%91
- Journal Information:
- Nature (London), Vol. 467, Issue 7319; ISSN 0028-0836
- Country of Publication:
- United States
- Language:
- English
Similar Records
Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells
Gating choreography and mechanism of the human proton-activated chloride channel $\mathrm{ASOR}$