Total chemical synthesis and high-resolution crystal structure of the potent anti-HIV protein AOP-RANTES

Background: RANTES is a CC-type chemokine protein that acts as a chemoattra ctant for several kinds of leukocytes, playing an important proinflammatory role. Entry of human immunodeficiency virus-1 (HIV-1) into cells depends o n the chemokine receptor CCR5. RANTES binds CCR5 and inhibits HIV-1 entry i nto peripheral blood cells. Interaction with chemokine receptors involves a distinct set of residues at the amino terminus of RANTES. This finding was utilized in the development of a chemically modified aminooxypentane deriv ative of RANTES, AOP-RANTES, that was originally produced from the recombin ant protein using semisynthetic methods. Results: AOP-RANTES has been produced by a novel total chemical synthesis t hat provides efficient, direct access to large amounts of this anti-HIV pro tein analog. The crystal structure of chemically synthesized AOP-RANTES has been solved and refined at 1.6 Angstrom resolution. The protein is a dimer , with the aminoterminal pentane oxime moiety clearly defined. Conclusions: Total chemical synthesis of AOP-RANTES provides a convenient m ethod of producing the multi-milligram quantities of this protein needed to investigate the molecular basis of receptor binding and antiviral activity . This work provides the first truly high-resolution structure of a RANTES protein, although the structure of RANTES was known from previous nuclear m agnetic resonance (NMR) determinations.