Original Articles
Sireesha Radarapu, Karli Geeth
Abstract
Nitrogenases from eight bacterial Rhodobacter species were analyzed and presented in this communication. The composition of alanine, glycine and leucine was high while low concentrations of asparagines, tyrosine, tryptophan, cysteine and lysine residues were seen when compared to other amino acids. The numbers of negative charged residues are more compared to positively charged residues. Molecular weight of AN2 was the highest while NIP3 nitrogenase had the lowest molecular weight. pI value of N2 was the highest with 6.1 while the lowest pI 4.98 was seen in NIP2. The instability index of all the nitrogenases varied while for most of them it was less than 40 except N3 showing that most of them are stable. The relative volume of protein occupied by aliphatic side chains was found to span within a range of 75 to 110. Secondary structural analysis of the nitrogenases showed the dominance of α- helices and random coils equally for all the nitrogenases. Beta turns were less in number for all the nitrogenases. SOSUI server analysis has shown that all the nitrogenases from Rhodobacter genus are soluble proteins except N3 which is a membrane protein