Bio Science Research Bulletin

The large carboxysomal protein CcmM is an important structural component of carboxysome and is very essential for initial assembly of triangular facets of carboxysome. They are distributed among different organisms and their role in carbon dioxide concentration mechanism is well understood but the evolutionary changes which had resulted in the modern version of the protein need to be traced out. CcmM protein sequence of Microcystis aeruginosa PCC 7806 [CA087105.1] was retrieved from NCBI. Protein BLAST analysis was performed and ten similar sequences were obtained. Phylogenetic tree based on neighbour joining method using MEGA 4.0, primary structure prediction using ProtParam software available in the ExPASy tools and comparison of molecular weights, pI, number of amino acids and instability index were done. ProtScale analysis of relative mutability and % of accessible residues were also carried out for the protein. Ala, Asn, Glu, Asp and Ser were top scorers for relative mutability and Lys and Ser for % of accessibility. GOR4 analysis revealed a structure comprising of 48.17% random coils, 35.17% a-helices and 16.67% extended strand. Geno3D analysis resulted in 5 models for which Ramachandran plots were obtained. Drawhca was used for hydrophobic cluster analysis and GlobPlot analysis for disorder regions. Swiss model analysis resulted in prediction of similar models and among them 5 theoretical models were selected for which Z scores Q mean comparison was conducted.