Towards a mechanism of function of the viral ion channel Vpu from HIV-1.
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.
Mehnert
T
T
Biomembrane Structure Unit, Department of Biochemistry, Oxford University, South Parks Road, Oxford, UK.
Lam
Y H
YH
Judge
P J
PJ
Routh
A
A
Fischer
D
D
Watts
A
A
Fischer
W B
WB
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
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