Cysteine-rich secretory proteins (CRISPs) are found in a wide variety of animal tissues, particularly the epididymis of mammals, and most reptile venoms appear to contain at least one isoform. Although several venom CRISPs have been assigned specific functions, many have not, and the biological significance of this family of proteins in venoms is not clear. In many colubrid venoms, they are major protein constituents, suggesting that they have an important role in envenomation. Like many other families of reptile toxins, CRISPs show a highly conserved molecular scaffold, and the sixteen cysteines and eight disulfides they form are 100% conserved. Because they are widely distributed among reptile venoms, show structural conservation, and many have been sequenced, they may have utility as phylogenetic markers. In general, venom CRISP relationships reflect established phylogenetic relationships among the species from which they are derived. By analogy with the three-finger toxins of reptile venoms, which also have a highly conserved protein scaffold stabilized by disulfides, one can expect that venom CRISPs will also show myriad pharmacological activities. Future efforts should be directed toward the elucidation of these activities, as they are an excellent protein family for structure-activity studies.
S. Mackessy, W. H. Heyborne
Journal name not available for this finding