In silico interaction analysis of maize transglutaminase

Abstract

Maize is an important cereal crop of the world, suitable to many agroecological zones. The productivity of maize depends on particular environment in which it is cultivated. A maize transglutaminase has been implicated in chloroplast bioenergetics. Over-expression of maize transglutaminase in Arabidopsis thaliana has been shown to improve the photosynthetic functionality of plant cells. However, over-expression in Nicotianatabacum reveals the propensity of maize transglutaminase to aggregate intracellularly. The resulting amyloid-like protein inclusions may have adverse effect on human health, as many human diseases are related to protein aggregation. Keeping the above in mind, present study was undertaken to find out the 3-dimensional structure of maize transglutaminase and determine the ‘aggregation hot-spots’ in its amino acid sequence. The protein model of maize transglutaminase was obtained via template-based tertiary structure prediction. All the 534 residues of the protein were modelled. Refinement of the obtained structure was performed, resulting in a model with 97.7% residues in the Rama favoured region. The protein has 49% region arranged in the form of eight helices. This was followed by analysis of protein sequence for aggregation hotspots. A motif in the terminal helix was found to be responsible for aggregation of the protein. The study discusses the orientation and function of the terminal helix, with a view to find possibilities to prevent protein aggregation inside the plant cells.