Your search returned the following 2 documents:

2. Computational Identification of Novel Amino-Acid Interactions in HIV Gag via Correlated Evolution
   Olga V. Kalinina, Heike Oberwinkler, Bärbel Glass, Hans-Georg Kräusslich, Robert B. Russell, and John A. G. Briggs
   PLoS ONE 7 (8): e42468,1-e42468,5, 2012
   
1. Modelling binding between CCR5 and CXCR4 receptors and their ligands suggests the surface electrostatic potential of the co-receptor to be a key player in the HIV-1 tropism
   Olga Kalinina, Nico Pfeifer, and Thomas Lengauer
   Retrovirology 10: 130 p., 2013