4.17. Cyanovirin-N
It is a 101-amino-acid-long, 11 kDa polypeptide isolated from Nostoc ellipsosporum, showing potent in vitro and in vivo activities against HIV and other lentiviruses in nanomolar concentrations. It interferes with the binding of HIV gp120 proteins with CD4+ receptors and the chemokine CCR5 or CXCR4 coreceptors of target cells, and, thus, inhibits fusion of HIV virus with CD4 cell membrane. It also inhibits herpes simplex virus-6 and measles virus in vitro.