The theta-defensin retrocyclin-1, also called RC-100, is a circular octadecapeptide containing an internal trisulfide ladder. Besides its antimicrobial activity, retrocyclin-1 has a remarkable ability to protect human cells in vitro from infection by T- and M-tropic strains of HIV-1. Its effectiveness against HIV-1 results from the prevention of viral entry, and is correlated with its ability to recognize and bind with high affinity to glycoproteins and glycolipids implicated in HIV-1 entry, such as gp120 (KD = 35.4 nM), CD4 (KD = 31 nM), and galactosylceramide (KD = 24.1 nM). Retrocyclin represents a new class of small molecule HIV-1 entry inhibitors.
W.Wang et al., J. Immunol., 170, 4708 (2003) A.M.Cole et al., Proc. Natl. Acad. Sci. USA, 99, 1813 (2002)
Sequence (One-Letter Code)
Sequence (Three-Letter Code)
Cyclo(-Gly-Ile-Cys-Arg-Cys-Ile-Cys-Gly-Arg-Gly-Ile-Cys-Arg-Cys-Ile-Cys-Gly-Arg) (Disulfide bonds between Cys³ and Cys¹⁶/Cys⁵ and Cys¹⁴/Cys⁷ and Cys¹²)