title: Glycosylation site-specific analysis of clade C HIV-1 envelope proteins.
abstract: The extensive glycosylation of HIV-1 envelope proteins (Envs), gp120/gp41, is known to play an important role in evasion of host immune response by masking key neutralization epitopes and presenting the Env glycosylation as "self" to the host immune system. The Env glycosylation is mostly conserved but continues to evolve to modulate viral infectivity. Thus, profiling Env glycosylation and distinguishing interclade and intraclade glycosylation variations are necessary components in unraveling the effects of glycosylation on Env's immunogenicity. Here, we describe a mass spectrometry-based approach to characterize the glycosylation profiles of two rVV-expressed clade C Envs by identifying the glycan motifs on each glycosylation site and determining the degree of glycosylation site occupancy. One Env is a wild-type Env, while the other is a synthetic "consensus" Env (C.CON). The observed differences in the glycosylation profiles between the two clade C Envs show that C.CON has more unutilized sites and high levels of high mannose glycans; these features mimic the glycosylation profile of a Group M consensus immunogen, CON-S. Our results also reveal a clade-specific glycosylation pattern. Discerning interclade and intraclade glycosylation variations could provide valuable information in understanding the molecular differences among the different HIV-1 clades and in designing new Env-based immunogens.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Eden P
authors.initials: EP
authors.lastname: Go
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.forename: Hua-Xin
authors.initials: HX
authors.lastname: Liao
authors.forename: Laura L
authors.initials: LL
authors.lastname: Sutherland
authors.forename: S Munir
authors.initials: SM
authors.lastname: Alam
authors.forename: Barton F
authors.initials: BF
authors.lastname: Haynes
authors.forename: Heather
authors.initials: H
authors.lastname: Desaire
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D006020:Glycopeptides / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D016415:Sequence Alignment
chemical_list: D006020:Glycopeptides; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D010446:Peptide Fragments; C514793:gp120 protein, Human immunodeficiency virus 1; C514787:gp41 protein, Human immunodeficiency virus 1