Models of ion pores in N-type voltage-gated calcium channels.
Two computer models of the outer vestibule of the pore of the N-type voltage-gated Ca2+ channel are predicted. The models are constructed from beta-hairpin peptide segments in the S5-S6 loops of each of the four domains that produce the channel. These hairpins together are modeled to form a short eight-stranded beta barrel. The models contain a ring of glutamates at the base of the barrel, which have been shown by mutagenesis experiments to function as a selectivity filter. These filters are suggested by the models to be of the correct dimensions to allow the permeation of a hydrated calcium ion, where the filter glutamates may substitute for molecules of water from the hydration shell of the ion. The models also suggest that a ring of threonines and an aspartate might be present between the mouth of the pore and the filter, and hence the models may prove useful in suggesting future mutagenesis experiments.
Doughty
S W
SW
Physical and Theoretical Chemistry Laboratory, University of Oxford, UK.
Blaney
F E
FE
Richards
W G
WG
D000595:Amino Acid Sequence; D002412:Cations / Q000737:chemistry; D003196:Computer Graphics; D003198:Computer Simulation; D015640:Ion Channel Gating; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008978:Mollusk Venoms / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D020866:omega-Conotoxin GVIA
D002412:Cations; D008978:Mollusk Venoms; D010455:Peptides; D020866:omega-Conotoxin GVIA