Interaction between human interleukin-16 and CD4 receptor of HIV-1

AIM: To study the interaction between human interleukin-16 (IL-16) and the receptor CD4 (T-lymphocyte differentiation antigen) of human immunodeficien cy virus type 1 (HIV-1). METHODS: Two structurally con served regions (SCRs ) of human IL-16 were built by the SYBYL/Biopolymer module using the corres ponding transmembrane (TM) domain of human interleukin-1 (HIL-4) and HIL-2 as the templates. The coordinates for amino-terminal residue sequence, carb oxyl-terminal residue sequences, and cytoplasm loops were generated using B iopolymer's LOOP SEARCH algorithm. RESULTS: HIL-16 first formed a homodimer , then contacted with CD4 dimer further forming a dimeric complex. Subseque ntly, the dimeric complex constructed the tetrameric complex by two disulfi de bridges between the cysteines of HIL-16 (Cys31-Cys31). CONCLUSION: The i nteraction model is useful to propose the action mechanism of HIL-16 and is beneficial for rational designing of novel anti-HIV drugs.