Subdomain folding and biological activity of the core structure from human immunodeficiency virus type 1 gp41: implications for viral membrane fusion.
The envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1) consists of two subunits, gp120 and gp41. The extraviral portion (ectodomain) of gp41 contains an alpha-helical domain that likely represents the core of the fusion-active conformation of the molecule. Here we report the identification and characterization of a minimal, autonomous folding subdomain that retains key determinants in specifying the overall fold of the gp41 ectodomain core. This subdomain, designated N34(L6)C28, is formed by covalent attachment of peptides N-34 and C-28 by a short flexible linker in place of the normal disulfide-bonded loop sequence. N34(L6)C28 forms a highly thermostable, alpha-helical trimer. Point mutations within the envelope protein complex that abolish membrane fusion and HIV-1 infectivity also impede the formation of the N34(L6)C28 core. Moreover, N34(L6)C28 is capable of inhibiting HIV-1 envelope-mediated membrane fusion. Taken together, these results indicate that the N34(L6)C28 core plays a direct role in the membrane fusion step of HIV-1 infection and thus provides a molecular target for the development of antiviral pharmaceutical agents.
Lu
M
M
Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10021, USA. mlu@mail.med.cornell.edu
Ji
H
H
Shen
S
S
D000595:Amino Acid Sequence; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011487:Protein Conformation; D017510:Protein Folding; D013329:Structure-Activity Relationship
D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41