title: The hinge portion of the S. aureus alpha-toxin crosses the lipid bilayer and is part of the trans-mouth of the channel.
abstract: This paper compares the functional properties of ion channels formed in planar lipid membranes by the wild and mutant Staphylococcus aureus alpha-toxin. It was shown that replacement of the amino acid Gly at position 130 by Cys in the primary structure of the toxin decreases the single-channel conductance with a concomitant decrease in the pH at which the channel becomes unable to discriminate between Cl- and K+ ions. The mutation also induced an increase in the asymmetry in the current-voltage relationship of the channel. The results of our experiments suggest that the trans-mouth of the channel is responsible for all the observed changes in channel properties. It was assumed that this entrance is built by the glycine-rich hinge portion of the toxin and is situated close to the surface of monolayer facing the trans-compartment.
authors.affiliation: Laboratory of Molecular Physiology, Institute of Physiology and Biophysics, Tashkent, Uzbekistan. kras@npd.ufpe.br
authors.forename: O V
authors.initials: OV
authors.lastname: Krasilnikov
authors.forename: L N
authors.initials: LN
authors.lastname: Yuldasheva
authors.forename: P G
authors.initials: PG
authors.lastname: Merzlyak
authors.forename: M F
authors.initials: MF
authors.lastname: Capistrano
authors.forename: R A
authors.initials: RA
authors.lastname: Nogueira
mesh_terms: D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004553:Electric Conductivity; D004594:Electrophysiology; D005947:Glucose / Q000378:metabolism; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism*; D008564:Membrane Potentials; D009154:Mutation; D010316:Particle Size; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism; D013211:Staphylococcus aureus / Q000737:chemistry*; D013395:Sucrose / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D006460:Hemolysin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010743:Phospholipids; C021091:staphylococcal alpha-toxin; D011092:Polyethylene Glycols; D013395:Sucrose; C024990:asolectin; D005947:Glucose