 |
PDBsum entry 2qhc
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Enzymatic and structural analysis of the i47a mutation contributing to the reduced susceptibility to HIV protease inhibitor lopinavir.
|
|
|
Authors
|
|
K.G.Sasková,
M.Kozísek,
M.Lepsík,
J.Brynda,
P.Rezácová,
J.Václavíková,
R.M.Kagan,
L.Machala,
J.Konvalinka.
|
|
|
Ref.
|
|
Protein Sci, 2008,
17,
1555-1564.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
Abstract
|
|
|
Lopinavir (LPV) is a second-generation HIV protease inhibitor (PI) designed to
overcome resistance development in patients undergoing long-term antiviral
therapy. The mutation of isoleucine at position 47 of the HIV protease (PR) to
alanine is associated with a high level of resistance to LPV. In this study, we
show that recombinant PR containing a single I47A substitution has the
inhibition constant (K(i) ) value for lopinavir by two orders of magnitude
higher than for the wild-type PR. The addition of the I47A substitution to the
background of a multiply mutated PR species from an AIDS patient showed a
three-order-of-magnitude increase in K(i) in vitro relative to the patient PR
without the I47A mutation. The crystal structure of I47A PR in complex with LPV
showed the loss of van der Waals interactions in the S2/S2' subsites. This is
caused by the loss of three side-chain methyl groups due to the I47A
substitution and by structural changes in the A47 main chain that lead to
structural changes in the flap antiparallel beta-strand. Furthermore, we
analyzed possible interaction of the I47A mutation with secondary mutations V32I
and I54V. We show that both mutations in combination with I47A synergistically
increase the relative resistance to LPV in vitro. The crystal structure of the
I47A/I54V PR double mutant in complex with LPV shows that the I54V mutation
leads to a compaction of the flap, and molecular modeling suggests that the
introduction of the I54V mutation indirectly affects the strain of the bound
inhibitor in the PR binding cleft.
|
|
|
|
|
|
|
|
Figure 1.
Model of HIV-1 PR with highlighted resistance-conferring
mutations studied in this work. Mutations in the PR1 isolated
from the patient are colored in yellow; color coding for other
mutations is: I47A (green), V32I (brown), and I54V (brown
stripes).
|
|
Figure 4.
Van der Waals interactions between PR and LPV lost due to the
I47A mutation. The distances are represented as dashed lines
with numbers in angstroms. (A) Wild-type PR (1MUI) complexed
with LPV. Segmentation of LPV into P2, P1, P1[prime prime or
minute], and P2[prime prime or minute] subsites is depicted. (B)
PR3 (I47A) complexed with LPV. (Thin gray lines) Superimposition
of LPV as bound to the wild-type PR.
|
|
|
|
|
|
The above figures are
reprinted
from an Open Access publication published by the Protein Society:
Protein Sci
(2008,
17,
1555-1564)
copyright 2008.
|
|
|
|
|
|
|
