Systematic Characterization of the ADP-Ribose Pyrophosphatase Family in the Cyanobacterium Synechocystis sp. Strain PCC 6803

Abstract

We have characterized four putative ADP-ribose pyrophosphatases Sll1054, Slr0920, Slr1134, and Slr1690 in the cyanobacterium Synechocystis sp. strain PCC 6803. Each of the recombinant proteins was overexpressed in Escherichia coli and purified. Sll1054 and Slr0920 hydrolyzed ADP-ribose specifically, while Slr1134 hydrolyzed not only ADP-ribose but also NADH and flavin adenine dinucleotide. By contrast, Slr1690 showed very low activity for ADP-ribose and had four substitutions of amino acids in the Nudix motif, indicating that Slr1690 is not an active ADP-ribose pyrophosphatase. However, the quadruple mutation of Slr1690, T73G/ I88E/K92E/A94G, which replaced the mutated amino acids with those conserved in the Nudix motif, resulted in a significant (6.1 ؋ 10 2 -fold) increase in the k cat value. These results suggest that Slr1690 might have evolved from an active ADP-ribose pyrophosphatase. Functional and clustering analyses suggested that Sll1054 is a bacterial type, while the other three and Slr0787, which was characterized previously (Raffaelli et al., FEBS Lett. 444:222-226, 1999), are phylogenetically diverse types that originated from an archaeal Nudix protein via molecular evolutionary mechanisms, such as domain fusion and amino acid substitution.

Functional definition of NrtR, a remnant regulator of NAD + homeostasis in the zoonotic pathogen Streptococcus suis

“…8). This is consistent with an earlier description of the Nudix hydrolase Slr1690 from Cyanobacterium species (32). Thus, it is plausible that the presence of an intact Nudix signature sequence is essential for the catalytic activity of a typical member of bifunctional NrtR.…”

Genomics-Guided Analysis of NAD Recycling Yields Functional Elucidation of COG1058 as a New Family of Pyrophosphatases

“…Besides possessing a completely different fold, COG1058 ADPRPs show unique Co +2 - and K + -dependence, with an optimum pH at 7.5, whereas Nudix ADPRPs are either Mg +2 - or Mn +2 -dependent, with a more alkaline optimum pH [34]. Nevertheless, COG1058 ADPRPs display a catalytic efficiency comparable to that of characterized bacterial Nudix ADPRPs [35], [36]. In addition, both types of ADPRPs exhibit a peculiar tendency to occur in a fused form with enzymes involved in the recycling to NAD of its by-products, suggesting a common functional connection with NAD regeneration (Figure 1).…”

Comparative proteogenomic analysis of the Leptospira interrogans virulence-attenuated strain IPAV against the pathogenic strain 56601

“…A high concentration of ADP-ribose in the cell causes nonenzymatic ADPribosylation, which inactivates various proteins and interferes with metabolic regulation via enzymatic ADPribosylation [55,56]. The ADP-ribose pyrophosphatases (ADPRases), which constitute a subfamily of the Nudix hydrolases, hydrolyze ADP-ribose to AMP and ribose- 5-phosphate.…”