INVESTIGADORES
CURATTI Leonardo
artículos
Título:
In vitro synthesis of the ironmolybdenum cofactor of nitrogenase from iron, sulfur, molybdenum, and homocitrate using purified proteins
Autor/es:
LEONARDO CURATTI; JOSE A. HERNANDEZ; ROBERT Y. IGARASHI; BASEM SOBOH; DEHUA ZHAO; LUIS M. RUBIO
Revista:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Referencias:
Año: 2007 vol. 104 p. 17626 - 17631
ISSN:
0027-8424
Resumen:
Biological nitrogen fixation, the
conversion of atmospheric N2 toNH3, is an essential
process in the global biogeochemical cycle of nitrogen that supports life on
Earth. Most of the biological nitrogen fixation is catalyzed by the molybdenum
nitrogenase, which contains at its active site one of the most complex metal
cofactors known to date, the ironmolybdenum cofactor (FeMo-co). FeMo-co is
composed of 7Fe, 9S, Mo, R-homocitrate, and one unidentified light atom.
Here we demonstrate the complete in vitro synthesis of FeMo-co from Fe2+,
S2-, MoO42- and R-homocitrate
using only purified Nif proteins. This synthesis provides direct biochemical support
to the current model of FeMo-co biosynthesis. A minimal in vitro system,
containing NifB, NifEN, and NifH proteins, together with Fe2 Fe2+,
S2-, MoO42-, R-homocitrate, S-adenosyl
methionine, and Mg-ATP, is sufficient for the synthesis of FeMo-co and the activation
of apo-dinitrogenase under anaerobic-reducing conditions.This in vitro system
also provides a biochemical approach to further study the function of accessory
proteins involved in nitrogenase maturation (as shown here for NifX and NafY).
The significance of these findings in the understanding of the complete FeMo-co
biosynthetic pathway and in the study of other complex Fe-S cluster
biosyntheses is discussed.