title: Molecular evolution of snake toxins: is the functional diversity of snake toxins associated with a mechanism of accelerated evolution?
abstract: Recent studies revealed that animal toxins with unrelated biological functions often possess a similar architecture. To tentatively understand the evolutionary mechanisms that may govern this principle of functional prodigality associated with a structural economy, two complementary approaches were considered. One of them consisted of investigating the rates of mutations that occur in cDNAs and/or genes that encode a variety of toxins with the same fold. This approach was largely adopted with phospholipases A2 from Viperidae and to a lesser extent with three-fingered toxins from Elapidae and Hydrophiidae. Another approach consisted of investigating how a given fold can accommodate distinct functional topographies. Thus, a number of topologies by which three-fingered toxins exert distinct functions were investigated either by making chemical modifications and/or mutational analyses or by studying the three-dimensional structure of toxin-target complexes. This review shows that, although the two approaches are different, they commonly indicate that most if not all the surface of a snake toxin fold undergoes natural engineering, which may be associated with an accelerated rate of evolution. The biochemical process by which this phenomenon occurs remains unknown.
authors.affiliation: Department of Chemistry, Faculty of Science, Fukuoka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: R
authors.initials: R
authors.lastname: Ménez
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: J M
authors.initials: JM
authors.lastname: Danse
authors.forename: Y
authors.initials: Y
authors.lastname: Shimohigashi
authors.forename: C
authors.initials: C
authors.lastname: Fromen
authors.forename: F
authors.initials: F
authors.lastname: Ducancel
authors.forename: S
authors.initials: S
authors.lastname: Zinn-Justin
authors.forename: M H
authors.initials: MH
authors.lastname: Le Du
authors.forename: J C
authors.initials: JC
authors.lastname: Boulain
authors.forename: T
authors.initials: T
authors.lastname: Tamiya
authors.forename: A
authors.initials: A
authors.lastname: Ménez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D012910:Snake Venoms; D012911:Snakes
chemical_list: D012910:Snake Venoms