Purification, Characterization, and cDNA Cloning of a New Fibrinogenlytic Venom Protein, Agkisacutacin, from Agkistrodon acutus Venom

Agkisacutacin is a new fibrinogenlytic protein from Agkistrodon acutus venom. It consists of two heterologous subunits linked by an intersubunit disulfide bond. The cDNAs encoding the two chains of Agkisacutacin were cloned from a λgt11 cDNA library of the snake venom gland and sequenced, including the leader peptides (23/23 amino acid residues) and mature subunits (129/123 amino acid residues). It is structurally related to the family of IX/X-binding protein (IX/X-bp)-like proteins and shows high similarity (α-70%/β-64%) to habu IX/X-bp from Trimeresurus flavoridis, but displays distinct biological activity with direct action on fibrinogen.