SYSTEM 
HIV-1 PR 
(BH5 isolate) with nonpeptide Cyclic Ureas as inhibitor XK263
HIVdb File 
hiv1dpm
PDB File 
1hvr
Company or Laboratory 
DuPont Merck Pharmaceutical Company
Year 
1994
INHIBITOR (Type) 
XK263 (nonpeptidic ureas inhibitor) 
Composition of the Inhibitor (Substrate) or Summary Formula 
[4R-( 4alpha, 5alpha, 6beta, 7beta)] - hexahydro - 5,6- dihydroxy - 1,3 - Bis [[ 2-naphtyl - methyl]- 4,7 - bis (phenylmetyl) - 2H, 1,3-diazepin - 2 - one
Schematic Formula 
XK263 
Resolution 
1.8Ao
R factor 
0.193
Space Group 
P61
Dimension of Elementary Cell 
a=62.80,b=62.80,c=83.50
a,b,g 
(alpha,beta,gamma)
a=b=90.00,g=120.00
Reference  P.Y.S.Lam, P.K.Jadhav, C.J.Eyermann, C.N. Hodge, Y.Ru, L.T.Bacheler, ..., S. Erickson - Viitanen; Science, 263, 380, 1994
Comment  Fundamental feature of these inhibitors is the cyclic urea carbonyl oxygen that mimics the hydrogen-bonding features of a key structural water molecule. There are hydroxyl groups covalently bound to SG Cys A67 and SG Cys B67.