Abstract:
Chlorophyll converts harvested light into chemical energy during the strategic process of photosynthesis in chloroplasts. Protochlorophyllide reduction in the chlorophyll formation is catalyzed by two complex enzymes; light-dependent protochlorophyllide oxidoreductase (LPOR) and dark-operated protochlorophyllide oxidoreductase (DPOR). Of these two, DPOR is a three-subunit complex in which ChlB plays a vital role in developing photosynthetically competent chloroplasts. What has not been reported before is the complete structural and functional annotation of ChlB subunit from plants. Sequence, structure and functional analyses of the ChlB subunit are performed using a blend of molecular biology and bioinformatics approaches to identify conserved residues and distribution of amino acids. Complete ChlB sequence analysis coupled with phylogenetic analysis, molecular docking and protein-protein interaction reveal that the ChlB is thermo-stable, acidic and hydrophilic in nature. The 3D structure (RMSD of 0.20Å) of ChlB is predicted and used as a target in docking and protein-protein interaction studies. Structural characterization of ChlB further elucidates that the amino acids Arg18, Asn175, Glu221 and Asp311 being important catalytic residues are involved in the basic function of ChlB and its interaction with other DPOR subunits. Further, the mutation analysis substantiates the central role of predicted catalytic residues in the structure of the ChlB. We conclude that the generated information will facilitate researchers in engineering chlorophyll pathway to improve photosynthesis in plants.
Keywords:
Photosynthesis
,
In silico analyses
,
Chloroplast
,
chlorophyll engineering