The key enzymes in cell wall biogenesis are the polysaccharide synthases and glycotransferases that catalyze the formation of the bonds between monosaccharides. The specificity of these enzymes determines the sequence, length and the branching pattern of sugar residues within a polysaccharide. Sequence similarity, the presence of certain motifs, hydrophobic cluster analysis and catalytic specificity have been used to categorize polysaccharide synthases and glycosyltransferases. In this work we are comparing the structure and dynamics of SpsA, which is a glycosyl transferase enzyme that is involved in making the spore coat of Bacillus subtilis, and cotton cellulose synthase. The crystal structure of SpsA was previously obtained by MIR techniques and the cotton synthase structure was predicted by us using bioinformatics and molecular modeling tools. For proteins, the important information about functional domains often arises through analysis of the effects of missense mutations in which one single amino acid is substituted for another. Numerous missense mutations in Arabidopsis CESA proteins have been identified and demonstrated by genetic experiments and plant phenotyping to confer essential functions. To understand how mutations affect similar proteins we performed structural alignment of SPSA structure with cotton and, then,  introduced mutations found in Arabidopsis and cotton into SPSA. We performed all atom implicit molecular dynamics study to estimate the temporal evolution of SpsA protein structure when the mutation is included.  We found that, while most of mutations have destabilizing effect, there are mutations that can also stabilize the structure

Structure similarity between glycosyltransferase enzyme from Bacillus subtilis and cotton cellulose synthase and the effect of mutations

243rd National Meeting (2012)

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