 Specific binding interactions between CCR5 and vicriviroc were first described in 2008.Specifically, the trifluoromethyl phenyl group of vicriviroc may interact strongly with I198 residue on the fifth transmembrane helix (TM5) of CCR5 through hydrophobic interactions.Additionally, electrostatic interactions may form between the positively charged tertiary nitrogen group of vicriviroc and the hydrophilic region provided by E238 residue on TM7 of CCR5.