In silico identification and evaluation of Bacillus subtilis cold shock protein B (cspB)-like plant RNA chaperones
Cold shock domain (CSD) proteins with nucleic acid binding properties are well conserved from bacteria to higher organisms. In bacteria, the cold shock proteins (CSPs) are single domain RNA chaperones, whereas in animals and plants, CSDs are accompanied by additional domains with roles in transcription regulation. Bacterial CSPs (Escherischia coli-cspA and Bacilus subtilis-cspB) have successfully imparted drought tolerance in transgenic plants; however, these cannot be deployed in food crops due to their low public acceptance of transgenics with bacterial genes. Therefore, this study aimed to identify CSPB-like proteins from plants that can be used for developing drought tolerant transgenic crops. Twelve single domain plant CSPs presenting >40% sequence identity with CSPB were identified. All 12 plant CSPs were modeled by homology modeling and refined by molecular dynamics simulation for 10 ns. Selected plant CSPs and CSPB exhibited high structural similarity (Tm-score: 0.63–0.86). Structure based phylogenetic analysis revealed that Triticum aestivum-csp1 and Aegilops tauschii-cspE are structurally closer to CSPB compared to their orthologs and paralogs. Molecular docking with three RNA molecules (5U, UC3U, and C2UC) indicates that Ricinus communis-csd1 and T. aestivum-csp1 have a binding pattern and docking scores similar to those of CSPB. Furthermore, MD simulations for 20 ns and analysis of RMSD, RMSF, Rg as well as the number of hydrogen bonds in all the three complexes revealed that plant CSP-RNA complexes behave in a similar manner to that of the CSPB-RNA complex, making them highly potential candidate genes for developing drought tolerance in transgenic plants.
Communicated by Ramaswamy H. Sarma