Biology Reference
In-Depth Information
Fig. 7.
gp120 core structure. Schematic representation of the tertiary
structure of the HIV-1
HXB-2
Env gp120 polypeptide highlighting the bridg-
ing sheet that connects the outer and inner domains as determined by the
crystallographic studies.
157
believed to mask the elements involved in CD4 binding and co-recep-
tor binding. It has been shown that the deletion of V1 or V1V2 loops
does not abrogate the functional activities of the envelope glycoprotein
because the recombinant V1 or V1V2 deleted viruses are fully repli-
cation-competent in human PBMC.
173
Furthermore, these deletions
in the context of Env protein also did not alter its ability to bind
sCD4.
139,174
This suggests that these modifications alone preserve the
integrity of important conserved epitopes on Env. Furthermore, dele-
tion of V1 and V2 loops has made the virus more susceptible to anti-
body-mediated neutralization; however, no improvement was
observed in terms of directing the immune response to the CD4
binding site.
139
Therefore, we introduced additional deletions in the
bridging sheet in an attempt to sufficiently expose the CD4 binding
