Azotobacter vinelandii nitrogenase“Kinetics of nif gene expression and insights into the roles of FdxN and NifQ in FeMo-co biosynthesis”
- Jiménez Vicente, Emilio
- Luis M. Rubio Herrero Directeur/trice
Université de défendre: Universidad Politécnica de Madrid
Fecha de defensa: 22 septembre 2014
- Juan Imperial Ródenas President
- José Manuel Palacios Alberti Secrétaire
- Abraham Esteve Núñez Rapporteur
- Enrique Flores García Rapporteur
- Antonia Herrero Moreno Rapporteur
Type: Thèses
Résumé
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.