Nitrogenase complex and its function.pptx

small yet descriptive presentation of the nitrogenase complex of cyanobacteria.

1. Bundelkhand university JHANSI Nitrogenase Complex By : Khushboo Mishra B.Sc. II year Department of Microbiology

2. Context Introduction of nitrogen and nitrogen fixation Nitrogenase complex Structure Reaction

3. INTRODUCTION Nitrogen is an essential constituent of all biomolecules both in plants and animals. Atmosphere consist of 78% of molecular nitrogen. Nitrogen fixation process f r ee up nitrogen atoms from their diatomic form to used in other ways. Nitrogen Fixation is a process of the biological conversion of the atmospheric nitrogen [ N2 ] into ammonia [ NH3 ].

4. NITROGENASE COMPLEX BNF is carried out by a highly conserved complex of proteins called as nitrogenase complex. Nitrogenase is an enzyme that catalyses the conversion of atmospheric dinitrogen and dihydrogen to ammonia N 2 + 3H 2 2NH 3

5. Nitrogenase complex is composed of two important proteins : Fe protein [ di-nitrogenase reductase ] Mo-Fe protein [ di-nitrogenase ] Neither of which has catalytic activity by itself.

6. Fe protein – is a dimer of 2 identical subunits. It contains a single 4 Fe - 4 S redox center bound between the subunits. This can be oxidized and reduced by 1 electron. The Mo-Fe protein binds substrate and reduces H + and N 2 to H 2 and ammonia . While the Fe protein receive electrons from ferredoxin , hydrolyses ATP and reduces the Fe-Mo protein.

7. Nitrogenase catalyzes the following reaction :- N 2 + 8H + + 16MgATP + 8e- 2NH3 + N2 + 16MgADP + 16P1 OR N 2 + 8flavodoxin ˉ + 8H + + 16MgATP ²ˉ + 18H 2 O 2NH 4 + 2OHˉ + 8 flavodoxin + 16MgADP ˉ + 16H 2 PO 4 ˉ + H 2 ­ nitrogenase

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