Insights into the structure-function relationship of brown plant hopper resistance protein, Bph14 of rice plant: a computational structural biology approach.

Brown plant hopper (BPH) is one of the major destructive insect pests of rice, causing severe yield loss. Thirty-two BPH resistance genes have been identified in cultivated and wild species of rice Although, molecular mechanism of rice plant resistance against BPH studied through map-based cloning, due to non-existence of NMR/crystal structures of Bph14 protein, recognition of leucine-rich repeat (LRR) domain and its interaction with different ligands are poorly understood. Thus, in the present study, in silico approach was adopted to predict three-dimensional structure of LRR domain of Bph14 using comparative modelling approach followed by interaction study with jasmonic and salicylic acids. LRR domain along with LRR-jasmonic and salicylic acid complexes were subjected to dynamic simulation using GROMACS, individually, for energy minimisation and refinement of the structure. Final binding energy of jasmonic and salicylic acid with LRR domain was calculated using MM/PBSA. Free-energy landscape analysis revealed that overall stability of LRR domain of Bph14 is not much affected after forming complex with jasmonic and salicylic acid. MM/PBSA analysis revealed that binding affinities of LRR domain towards salicylic acid is higher as compared to jasmonic acid. Interaction study of LRR domain with salicylic acid and jasmonic acid reveals that THR987 of LRR form hydrogen bond with both complexes. Thus, THR987 plays active role in the Bph14 and phytochemical interaction for inducing resistance in rice plant against BPH. In future, Bph14 gene and phytochemicals could be used in BPH management and development of novel resistant varieties for increasing rice yield.

In silico analysis of single nucleotide polymorphism (SNP) in human TNF-α gene.

The TNF-α gene mutations are seen in many diseases especially inflammatory diseases. Hence, before planning a larger population study, it is advisable to sort out the possible functional SNPs. To accomplish this goal, data available in the dbSNP database and different computer programs can be used. Therefore, this study was undertaken to find the functional nsSNPs (non-synonymous single nucleotide polymorphisms) in TNF-α. Out of the total 169 SNPs, 48 were nsSNPs (non-synonymous single nucleotide polymorphisms), 23 occurred in the mRNA 3' UTR, 10 occurred in 5' UTR region, 41 occurred in intronic regions and the rest were other types of SNPs. SIFT and PolyPhen predicted 2 out of 48 nsSNPs as damaging. Among the predicted nsSNPs, rs4645843 and rs1800620 were identified as deleterious and damaging by the SIFT (Sorting Intolerant from Tolerant) and PolyPhen programs. Additionally, I-Mutant and nsSNPAnalyzer showed a decrease in stability for these nsSNPs upon mutation. Protein structural analysis with these amino acid variants was performed by using I-Mutant, Swiss PDB viewer, ANOLEA (Atomic Non-Local Environment Assessment), MUSTER (MUlti-Sources ThreadER) and NOMAD-Ref servers to check their molecular dynamics and energy minimization calculations. This study suggested that P84L and A94T variants of TNF-α could directly or indirectly destabilize the amino acid interactions and hydrogen bond networks thus explaining the functional deviations of protein to some extent.