In silico analysis of the structural diversity and interactions between invertases and invertase inhibitors from potato (Solanum tuberosum L.).

We performed sequence diversity, phylogenetic profiling, 3D structure modelling and in silico interactions between invertases (cell wall/apoplastic and vacuolar) and invertase inhibitors (cell wall/apoplastic and vacuolar) from potato. Cloning and sequencing of invertase inhibitors was performed from different potato cultivars. The comparison of the protein sequences of the different isoforms of invertases and invertase inhibitors exhibited insertions and deletions as well as the variation in terms of amino acid residues. Furthermore, the phylogenetic tree analysis displayed two groups of invertase inhibitors corresponding to the cell wall/apoplast and vacuole. Using Phyre2 protein homology recognition engine, it revealed that the structure of invertase inhibitors was predominantly α-helical and that of invertase was α helices and β strands. Results of the Ramachandran plots for each structure showed that the percentage of amino acid residues in favoured region and in allowed region. Also, the Z score and QMEAN score indicated overall good, acceptable and reliable models. In silico interactions between different isoforms of invertase and invertase inhibitors suggested that cell wall/ apoplastic invertase inhibitor exhibited stronger interaction with vacuolar invertase compared to the vacuolar invertase inhibitor. In silico interactions provides valuable information in selecting the appropriate combinations of invertase and invertase inhibitor. Therefore, a better understanding of the interactions between specific invertase and invertase inhibitor alleles will be helpful for an intelligent manipulation of the cold-induced sweetening process of potato tubers. © King Abdulaziz City for Science and Technology 2020.