Peptide ligands selected with CD4-induced epitopes on native dualtropic HIV-1 envelope proteins mimic extracellular coreceptor domains and bind to HIV-1 gp120 independently of coreceptor usage.
During HIV-1 entry, binding of the viral envelope glycoprotein gp120 to the cellular CD4 receptor triggers conformational changes resulting in exposure of new epitopes, the highly conserved CD4-induced (CD4i) epitopes that are essential for subsequent binding to chemokine receptor CCR5 or CXCR4. Due to their functional conservation, CD4i epitopes represent attractive viral targets for HIV-1 entry inhibition. The aim of the present study was to select peptide ligands for CD4i epitopes on native dualtropic (R5X4) HIV-1 envelope (Env) glycoproteins by phage display. Using CD4-activated retroviral particles carrying Env from the R5X4 HIV-1 89.6 strain as the target, we performed screenings of random peptide phage libraries under stringent selection conditions. Selected peptides showed partial identity with amino acids in the extracellular domains of CCR5/CXCR4, including motifs rich in tyrosines and aspartates at the N terminus known to be important for gp120 binding. A synthetic peptide derivative (XD3) corresponding to the most frequently selected phages was optimized for Env binding on peptide arrays. Interestingly, the optimized peptide could bind specifically to gp120 derived from HIV-1 strains with different coreceptor usage, competed with binding of CD4i-specific monoclonal antibody (MAb) 17b, and interfered with entry of both a CCR5 (R5)-tropic and a CXCR4 (X4)-tropic Env pseudotyped virus. This peptide ligand therefore points at unique properties of CD4i epitopes shared by gp120 with different coreceptor usage and could thus serve to provide new insight into the conserved structural details essential for coreceptor binding for further drug development.
Dervillez
Xavier
X
Georg-Speyer-Haus, Institute for Biomedical Research, Paul-Ehrlich-Str. 42-44, 60596 Frankfurt am Main, Germany.
Klaukien
Volker
V
Dürr
Ralf
R
Koch
Joachim
J
Kreutz
Alexandra
A
Haarmann
Thomas
T
Stoll
Michaela
M
Lee
Donghan
D
Carlomagno
Teresa
T
Schnierle
Barbara
B
Möbius
Kalle
K
Königs
Christoph
C
Griesinger
Christian
C
Dietrich
Ursula
U
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015704:CD4 Antigens / Q000378:metabolism*; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D015752:Genes, env; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology* / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D017434:Protein Structure, Tertiary; D019713:Receptors, CCR5 / Q000737:chemistry / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000737:chemistry / Q000378:metabolism; D014161:Transduction, Genetic; D053586:Virus Internalization
D015704:CD4 Antigens; C527276:CXCR4 protein, human; D017931:DNA Primers; D004279:DNA, Viral; D015699:HIV Envelope Protein gp120; D008024:Ligands; D019151:Peptide Library; D010455:Peptides; D019713:Receptors, CCR5; D019718:Receptors, CXCR4; C514793:gp120 protein, Human immunodeficiency virus 1