Properties of the halophilic nuclease of a moderate halophile, Micrococcus varians subsp. halophilus

Abstract

The halophilic nuclease of Micrococcus varians ATCC 21971 hydrolyzed thymidine 5'-monophospho-p-nitrophenyl ester at a rate that increased with the NaCl concentration up to saturation. The nuclease attacked RNA and DNA exonucleolytically and processively, producing 5'-mononucleotides. The molecular weight of the enzyme as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 99,000, approximately the same as that previously determined for the native enzyme. Examination of amino acid composition showed that acidic amino acids were in high excess over basic amino acids.

Isolation and Molecular Level Identification of DNase Producing Halophilic Bacillus cereus Family Isolates from Marine Sediment Sample

“…There are only few reports on halophilic nuclease production by halophiles, including Micrococcus variants, Var halophilus (Kamekura and Onishi 1978) and Bacillus halophilus (Onishi et al, 1983, Ventosa 2015. In order to know the halophilic nature and capacity of DNase production of all strains it is necessary to check the growth and DNase production at various NaCl concentrations (Table.…”

Production and function of enzymes of eubacterial halophiles

“…Production of the nuclease by this halophile was maximal at 2 to 3 M NaC1 or KC1 [7]. The nuclease was purified to an electrophoretically homogeneous state, using ammonium sulfate or ethanol precipitation, hydroxyapatite column chromatography or gel filtration in the presence of 2 M NaC1, and DEAE-Sephadex ion exchange chromatography in 0.3 M NaC1 [11]. The enzyme showed a maximal activity at saturated NaCI concentration with a synthetic substrate, thymidine-5'-monophospho-p-nitrophenyl ester [11].…”

“…This nuclease was inactivated by dialyzing against hypotonic solutions such as 0.2 M NaCI: however, redialysis against 3.4 M NaC1 buffer reactivated the once inactivated nuclease [7]. The digestion products of RNA with the halophilic nuclease (nuclease H) were 5'-ribonucleotides [11]; the application of crude culture filtrates for the commercial production of a flavoring agent, 5'-guanylic acid, was reported [12].…”

Halophilic Nuclease of a Moderately Halophilic Bacillus sp.: Production, Purification, and Characterization

“…The previous studies on enzyme production by the isolates showed that a moderate halophile, Micrococcus varians subsp. halophilus, produced a halophilic nuclease (7,8), and two other moderate halophiles, Micrococcus halobius (14) and Acinetobacter sp. (13), produced amylases.…”

“…However, there was no description on the effect of NaCl concentrat Permanent address: Noda Institute for Scientific Research, Noda-shi, Chiba-ken, Japan 278. tion on the enzyme activity. As for halophilic nucleases, only nuclease H of M. varians has so far been reported (7,8). It seems interesting to compare the characteristics of the purified enzyme preparations of both moderate halophiles, Bacillus sp.…”