title: The ineluctable requirement for the trans-iron elements molybdenum and/or tungsten in the origin of life.
abstract: An evolutionary tree of key enzymes from the Complex-Iron-Sulfur-Molybdoenzyme (CISM) superfamily distinguishes "ancient" members, i.e. enzymes present already in the last universal common ancestor (LUCA) of prokaryotes, from more recently evolved subfamilies. The majority of the presented subfamilies and, as a consequence, the Molybdo-enzyme superfamily as a whole, appear to have existed in LUCA. The results are discussed with respect to the nature of bioenergetic substrates available to early life and to problems arising from the low solubility of molybdenum under conditions of the primordial Earth.
authors.forename: Barbara
authors.initials: B
authors.lastname: Schoepp-Cothenet
authors.forename: Robert
authors.initials: R
authors.lastname: van Lis
authors.forename: Pascal
authors.initials: P
authors.lastname: Philippot
authors.forename: Axel
authors.initials: A
authors.lastname: Magalon
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Russell
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Nitschke