A Novel Synthetic Chemokine Containing D-Amino Acids That Binds to the CXCR4 Receptor and Inhibits HIV-1 Infection.

The viral inflammatory protein II (vMIP-II) is a mammalian chemokine homologue encoded by Kaposi’s Sarcoma-associated herpesvirus. vMIP-II shows a broad spectrum binding activity to CXC, CC and CX3C chemokine receptors. Particularly, vMIP-II binds to CXCR4 and CCR5 which are two major coreceptors for HIV-1 virus entry and infection. In our previous study, we reported an all D-amino acids peptide (DV1) derived from the N-terminus of vMIP-II showing high binding affinity to CXCR4. To study the binding mechanism of vMIP-II with CXCR4, we attached the first 10 D-amino acid residues of this peptide to the N-terminus of vMIP-II, before the first cysteine and synthesized a new chemokine analogue of vMIP-II which we named D10-vMIP-II. Despite of the chiral inverse of the N-terminal residues, D10-vMIP-II shows high CXCR4 binding affinity and inhibits the HIV-1 virus entry as vMIP-II. To explore the structural features of D10-vMIP-II, we determined its crystal structure in high resolution. The crystal structure shows that D10-vMIP-II adopts the same structural folding pattern as vMIP-II except for structural changes at the N-terminus, N-loop and the 30’s loop region, suggesting that the local structures at the N-terminus, N-Loop and the 30’s loop region can be adjusted coordinately. This novel synthetic SMM-Chemokine strongly inhibits the entry and replication of HIV-1 via CXCR4. Our studies demonstrate a new promising lead for the development of therapeutic agents targeted to the HIV-1 entry mechanism.