Scytovirin is a protein from the cyanobacteria Scytonema varium with anticytopathic activity against some strains of HIV. The protein, which adopts a monomeric assembly, has two repeats that form similarly structured domains. Remarkably, it has a high percentage of cysteine residues, all participating in disulfide bonds [1-3]. This family also includes proteins from Proteobacteria and plants.

1: Atomic-resolution crystal structure of the antiviral lectin scytovirin. Moulaei T, Botos I, Ziolkowska NE, Bokesch HR, Krumpe LR, McKee TC, O'Keefe BR, Dauter Z, Wlodawer A; Protein Sci. 2007;16:2756-2760. PMID:17965185

2: The novel fold of scytovirin reveals a new twist for antiviral entry inhibitors. McFeeters RL, Xiong C, O'Keefe BR, Bokesch HR, McMahon JB, Ratner DM, Castelli R, Seeberger PH, Byrd RA; J Mol Biol. 2007;369:451-461. PMID:17434526

3: A potent novel anti-HIV protein from the cultured cyanobacterium Scytonema varium. Bokesch HR, O'Keefe BR, McKee TC, Pannell LK, Patterson GM, Gardella RS, Sowder RC 2nd, Turpin J, Watson K, Buckheit RW Jr, Boyd MR; Biochemistry. 2003;42:2578-2584. PMID:12614152