title: Towards a mechanism of function of the viral ion channel Vpu from HIV-1.
abstract: Vpu, an integral membrane protein encoded in HIV-1, is implicated in the release of new virus particles from infected cells, presumably mediated by ion channel activity of homo-oligomeric Vpu bundles. Reconstitution of both full length Vpu(1-81) and a short, the transmembrane (TM) domain comprising peptide Vpu(1-32) into bilayers under a constant electric field results in an asymmetric orientation of those channels. For both cases, channel activity with similar kinetics is observed. Channels can open and remain open within a broad series of conductance states even if a small or no electric potential is applied. The mean open time for Vpu peptide channels is voltage-independent. The rate of channel opening shows a biphasic voltage activation, implicating that the gating is influenced by the interaction of the dipole moments of the TM helices with an electric field.
authors.affiliation: Biomembrane Structure Unit, Department of Biochemistry, Oxford University, South Parks Road, Oxford, UK.
authors.forename: T
authors.initials: T
authors.lastname: Mehnert
authors.forename: Y H
authors.initials: YH
authors.lastname: Lam
authors.forename: P J
authors.initials: PJ
authors.lastname: Judge
authors.forename: A
authors.initials: A
authors.lastname: Routh
authors.forename: D
authors.initials: D
authors.lastname: Fischer
authors.forename: A
authors.initials: A
authors.lastname: Watts
authors.forename: W B
authors.initials: WB
authors.lastname: Fischer
mesh_terms: D000595:Amino Acid Sequence; D004553:Electric Conductivity; D015497:HIV-1 / Q000502:physiology*; D054298:Human Immunodeficiency Virus Proteins; D015640:Ion Channel Gating / Q000502:physiology; D007473:Ion Channels / Q000737:chemistry / Q000502:physiology; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins / Q000737:chemistry / Q000502:physiology*; D000086082:Viroporin Proteins
chemical_list: D054298:Human Immunodeficiency Virus Proteins; D007473:Ion Channels; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D054334:Viral Regulatory and Accessory Proteins; C514859:vpu protein, Human immunodeficiency virus 1; D000086082:Viroporin Proteins