Classification, characterization and structural analysis of sugar nucleotidylyltransferase family of enzymes.

Vaibhav Singh, Bais and Pooja, Aggarwal and Prashant, Bharadwaj and Balaji, Prakash (2020) Classification, characterization and structural analysis of sugar nucleotidylyltransferase family of enzymes. Biochemical and Biophysical Research Communications, 525 (3). pp. 780-785. ISSN 0006-291X

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Abstract

Sugar Nucleotidyl Transferases (SNTs) constitute a large family of enzymes that play important metabolic roles. Earlier, for one such SNT, termed N-acetylglucosamine-1-phosphate uridyltransferase- GlmU, we had established that two magnesium ions - Mg2þ A and Mg2þ B - catalyze the sugar-nucleotidyl transfer reaction. Despite a common structural framework that SNTs share, we recognized key differences around the active-site based on the analysis of available structures. Based on these differences, we had classified SNTs into two major groups, Group - I & II; and further, variation in ‘Mg2þ A-stabilizing motifs’ led us to sub-classify them into five distinct sub-groups. Since group specific conservation of ‘Mg2þ A-stabilizing motifs’ was based only for 45 available structures, here we validate this via an exhaustive analysis of 1,42,025 protein sequences. Previously, we had hypothesized that a metal-ion-catalyzed mechanism would be operative in all SNTs. Here, we validate it biochemically and establish that Mg2þ is a strict requirement for nucleotidyl transfer reactions in every group or sub-group and that a common metal ion dependent mechanism operates in SNTs. Further, mutating Mg2þ A coordinating residue in each subgroup led to abolished catalysis, indicating an important role for both of these residues and suggest that SNTs employ variations over ‘a conserved catalytic mechanism mediated by Mg2þ ion(s)’, to bring about functional diversity. This would constitute a comprehensive study to establish the catalytic mechanism across the family of SNTs.

Item Type:	Article
Uncontrolled Keywords:	Classification Magnesium Catalytic mechanism Sugar nucleotidylyltransferase SNT
Subjects:	600 Technology > 08 Food technology > 16 Nutritive value > 05 Enzymes 600 Technology > 08 Food technology > 25 Sugar/Starch/Confectionery
Divisions:	Molecular Nutrition
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	27 Nov 2020 04:40
Last Modified:	27 Nov 2020 04:40
URI:	http://ir.cftri.res.in/id/eprint/14652

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