A Novel Cold-Adapted and Salt-Tolerant RNase R from Antarctic Sea-Ice Bacterium Psychrobacter sp. ANT206

Abstract

A novel RNase R, psrnr, was cloned from the Antarctic bacterium Psychrobacter sp. ANT206 and expressed in Escherichia coli (E. coli). A bioinformatics analysis of the psrnr gene revealed that it contained an open reading frame of 2313 bp and encoded a protein (PsRNR) of 770 amino acids. Homology modeling indicated that PsRNR had reduced hydrogen bonds and salt bridges, which might be the main reason for the catalytic efficiency at low temperatures. A site directed mutation exhibited that His 667 in the active site was absolutely crucial for the enzyme catalysis. The recombinant PsRNR (rPsRNR) showed maximum activity at 30 °C and had thermal instability, suggesting that rPsRNR was a cold-adapted enzyme. Interestingly, rPsRNR displayed remarkable salt tolerance, remaining stable at 0.5–3.0 M NaCl. Furthermore, rPsRNR had a higher kcat value, contributing to its efficient catalytic activity at a low temperature. Overall, cold-adapted RNase R in this study was an excellent candidate for antimicrobial treatment.

AhaP, A Quorum Quenching Acylase from Psychrobacter sp. M9-54-1 That Attenuates Pseudomonas aeruginosa and Vibrio coralliilyticus Virulence

“…Cold-adapted enzymes are considered to have potential biotechnological and industrial applications that require activity at mild temperatures and rapid heat inactivation rates, such as that found in molecular biology, medical research, food/feed processing, pharmaceuticals, detergents and cosmetics [ 45 , 47 , 48 , 49 ]. With regard to Psychrobacter, cold-adapted enzymes, such as ribonucleases, proteases, esterases and lipases, have been found in some species of this genus [ 45 , 47 , 50 , 51 , 52 ]. Nevertheless, the production of compounds that interfere with quorum sensing (QS) in Psychrobacter strains has been the subject of a limited number of studies.…”

Bacterial Communities of Sediments in a Seawater-Freshwater Transition Zone During the Wet and Dry Seasons in Pearl River Estuary

“…It suggested that the identi ed keystone bacteria may be resistant to salinity. In fact, some members of Moraxellaceae and Planococcaceae have been isolated from various hypersaline habitats [58][59][60][61].…”

“…This nding is consistent with our result that Psychrobacter was enriched in January when low temperature condition existed. Besides, some strains of Psychrobacter have been isolated and/or detected in variety of hypersaline surroundings [59,[62][63][64]. Psychrobacter sp.…”

“…Psychrobacter sp. ANT206 was isolated from Antarctic sea-ice, which not only had high catalytic e ciency at low temperatures but also displayed remarkable salt tolerance [59]. Psychrobacter was identi ed as the predominant bacterium at high salinity (15 g L − 1 NaCl) [65].…”

Molecular insights into the ecology of a psychrotolerant Pseudomonas syringae

“…RNase R from the Antarctic bacterium Psychrobacter sp. ANT206 was also found to be thermally instable but showed efficient catalytic activity at 30°C, suggesting that it is also cold‐adapted (Wang et al ., 2019). Since the discovery of RNase R as a novel component of RNA degradosome machinery in P. syringae , its genetic and biochemical characterization has demonstrated that the RNase R‐mediated RNA metabolism is crucial for cold adaptation (Fig.…”