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Keywords:

  • Vpu HIV-1;
  • membrane protein;
  • assembly;
  • molecular dynamics simulations;
  • docking approach

Different routes of assembly are probed for the transmembrane domain (TMD) of the bitopic membrane protein Vpu from HIV-1. Vpu is responsible for the amplification of viral release from the host cell. The mode of action includes (i) heteroassembly with host factors and (ii) the formation of homo-oligomers, which are able to conduct ions across the lipid membrane. Two different routes of assembling short sequences of the N terminus, including the TMD of Vpu, Vpu1–32, and Vpu8–26, are presented by using a combination of classical molecular dynamics (MD) simulations combined with a docking approach. The rim of alanines (Ala-8, -11, -15, and -19) resembles an interlocking motif for the sequential assembly into a dimer and trimer. Simultaneous assembly results in oligomeric bundles (trimers to pentamers) with either tryptophans (Trp-23) or purely hydrophobic residues facing the center. Bundles, with serines facing the pore (Ser-24), are energetically not the lowest structures. For pentameric bundles with Ser-24 facing the pore, no water column develops during a short 25 ns MD simulation. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 517–529, 2013.