Correlation between the sucrose synthase protein subfamilies, variations in structure and expression in stress-derived expressed sequence tag datasets

Sucrose synthase is a key regulatory protein, and a potential biomarker for abiotic stress response in plants. These metabolic enzymes have been extensively examined for their varied functional roles. The upregulation of this Pi- and adenylate-independent glycolytic enzyme in different environmental contexts has also been extensively characterized. Here we present an analysis of the evolutionary features of sucrose synthases in an effort to correlate variations in sequence to the structure and function of this protein and its potential implication for the stress response mechanism in plants as evidenced from transcript distribution studies. An analysis of the evolutionary characteristics of this enzyme is useful given the role of this protein in sugar sensing, sugar import to sink tissues and plant development. Based on the secondary structural features of sucrose synthases and mapping of sequence variations in the context of the fold of these proteins, we note evolutionarily conserved amino acids of potential functional significance. In addition, we also observe the presence of target peptides in some of these proteins suggesting potential cellular localization. The results presented in this manuscript could aid ongoing studies on this protein as a potential biomarker and candidate gene for environmental stress