The ectodomain of HIV-1 env subunit gp41 forms a soluble, alpha-helical, rod-like oligomer in the absence of gp120 and the N-terminal fusion peptide.
The human immunodeficiency virus-1 (HIV-1) envelope glycoprotein is composed of a soluble glycopolypeptide gp120 and a transmembrane glycopolypeptide gp41. These subunits form non-covalently linked oligomers on the surface of infected cells, virions and cells transfected with the complete env gene. Two length variants of the extracellular domain of gp41 (aa 21-166 and aa 39-166), that both lack the N-terminal fusion peptide and the C-terminal membrane anchor and cytoplasmic domain, have been expressed in insect cells to yield soluble oligomeric gp41 proteins. Oligomerization was confirmed by chemical cross-linking and gel filtration. Electron microscopy and circular dichroism measurements indicate a rod-like molecule with a high alpha-helical content and a high melting temperature (78 degrees C). The binding of monoclonal antibody Fab fragments dramatically increased the solubility of both gp41 constructs. We propose that gp41 folds into its membrane fusion-active conformation, when expressed alone.
Weissenhorn
W
W
Laboratory of Molecular Medicine, Howard Hughes Medical Institute, Children's Hospital, Boston, MA 02215, USA.
Wharton
S A
SA
Calder
L J
LJ
Earl
P L
PL
Moss
B
B
Aliprandis
E
E
Skehel
J J
JJ
Wiley
D C
DC
D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D004220:Disulfides / Q000737:chemistry; D015752:Genes, env; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120 / Q000737:chemistry; D015700:HIV Envelope Protein gp41 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D015497:HIV-1 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D007313:Insecta; D008854:Microscopy, Electron; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012995:Solubility; D013816:Thermodynamics; D014760:Viral Fusion Proteins / Q000737:chemistry
D000911:Antibodies, Monoclonal; D004220:Disulfides; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D007140:Immunoglobulin Fab Fragments; D014760:Viral Fusion Proteins