Comprehensive analysis of beta-galactosidase protein in plants based on Arabidopsis thaliana

Beta-galactosidases (beta gals) (EC 3.2.1.23) have been detected in a wide range of plant organs and tissues and are described by their ability to hydrolyze terminal nonreducing beta-D-galactosyl residues from beta-D-galactosides. In this study, 92 beta gal protein sequences from different plants, 7 animal samples including human and mouse, 3 samples from bacteria including Escherichia coli, and 4 samples from insects including Drosophila melanogaster were aligned. Sequences were analyzed by computational tools to predict the protein properties, such as molecular mass, isoelectric point, signal peptide, motifs, transmembrane domain, and secondary and spatial structure. Protein structure analysis revealed there is a high identity between plants and other organisms. The modeled beta gal has a typical spatial structure with catalytic regions. The 3-dimensional model of Arabidopsis thaliana beta gal (Accession Number: NP_001154292) was further checked by PROCHECK algorithm, and showed the majority of the amino acid residues were located in the most-favored regions in a Ramachandran plot. This result suggested that the simulated 3-dimensional structure was reliable. Phylogenetic analysis indicated that A. thaliana beta gal has a close relationship with some plants' beta gal from different families such as Malvaceae, Solanaceae, and Poaceae. According to these results, beta gals should be derived from a common ancestor.