CRISP family

General Activity
Cysteine-rich secretory proteins (CRISPs) are glycoproteins which have broad diversified functions. They are hypothesized to play important roles in mammalian reproduction (Cohen et al., 2011).

In reptilian venom, they are toxic through several mechanisms, including, among others, blockage of cyclic nucleotide-gated channels (for example, see pseudechetoxin and pseudecin), inhibition of contraction of rat tail arterial smooth muscle induced by high concentrations of potassium ions (see ablomin, triflin and latisemin), and inhibition of voltage-gated and calcium-activated potassium channels as well as ryanodine receptors (see natrin-1)

Sequence characteristics
CRISPs are single-polypeptide proteins with molecular weights of 20 to 30 kDa which are known to have a high degree of amino acid sequence similarity and a highly conserved specific pattern of 16 cysteine residues. Ten of these cysteine residues form an integral part of the highly conserved cysteine-rich domain (CRD) at the C-terminus. The CRD is composed of two domains, a hinge region and an ion channel regulator (ICR) domain.