Azotobacter vinelandii nitrogenase“Kinetics of nif gene expression and insights into the roles of FdxN and NifQ in FeMo-co biosynthesis”

  1. Jiménez Vicente, Emilio
Dirigida por:
  1. Luis M. Rubio Herrero Director/a

Universidad de defensa: Universidad Politécnica de Madrid

Fecha de defensa: 22 de septiembre de 2014

Tribunal:
  1. Juan Imperial Ródenas Presidente/a
  2. José Manuel Palacios Alberti Secretario/a
  3. Abraham Esteve Núñez Vocal
  4. Enrique Flores García Vocal
  5. Antonia Herrero Moreno Vocal

Tipo: Tesis

Resumen

The Molybdenum-nitrogenase is responsible for most biological nitrogen fixation activity (BNF) in the biosphere. Due to its great agronomical importance, it has been the subject of profound genetic and biochemical studies. The Mo nitrogenase carries at its active site a unique iron-molybdenum cofactor (FeMoco) that consists of an inorganic 7 Fe, 1 Mo, 1 C, 9 S core coordinated to the organic acid homocitrate. Biosynthesis of FeMo-co occurs outside nitrogenase through a complex and highly regulated pathway involving proteins acting as molecular scaffolds, metallocluster carriers or enzymes that provide substrates in appropriate chemical forms. Specific expression regulatory factors tightly control the accumulation levels of all these other components. Insertion of FeMo-co into a P-cluster containing apo-NifDK polypeptide results in nitrogenase reconstitution. Investigation of FeMo-co biosynthesis has uncovered new radical chemistry reactions and new roles for Fe-S clusters in biology.