Presentation on theme: "Enzyme catalyzing Nitrogen Fixation in Bacteria Root nodules on legumes."— Presentation transcript:
Enzyme catalyzing Nitrogen Fixation in Bacteria Root nodules on legumes
Nitrogenase is the enzyme found in a variety of bacteria, some of them symbiotic with plants catalyzes the conversion of molecular nitrogen (N 2 ) from the air into ammonia (NH 3 ). It is found in a variety of bacteria, some of them symbiotic with plants.
Choosing the sequence to compare Nitrogenase consists of a molybdenum-iron (MoFe) protein and an iron (Fe) protein. The MoFe protein contains 2 alpha protein chains and 2 beta protein chains.
Trials and Errors Constructed a phylogenetic tree of the Mo-Fe protein of nitrogenase from published nucleic acid data. Tried to get a more coherent tree by eliminating some of the sequences. Tree still not revealing. Mistake: using nucleotides, switched to amino acid sequences for the alpha and beta chains.
Amino Acid sequence Obtained amino acid sequence of alpha and beta subunits of MoFe protein from Azotobacter vinelandii Did an alignment on alpha and beta subunits and found 20.1% identity and, 78% global alignment, suggesting that alpha and beta chains are the product of gene duplication.
Crystallographic structure Found crystallographic structure for MoFe protein from A. vinelandii shown on next slide.