Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate
ABSTRACT We isolated a gram-positive, halotolerant psychrophile from a hypersaline pond located on the McMurdo Ice Shelf in Antarctica. A phylogenetic analysis of the 16S rRNA gene sequence of this organism showed that it is a member of the genus Planococcus . This assignment is consistent with the...
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Online Access: | http://dx.doi.org/10.1128/aem.66.6.2438-2444.2000 https://journals.asm.org/doi/pdf/10.1128/AEM.66.6.2438-2444.2000 |
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crasmicro:10.1128/aem.66.6.2438-2444.2000 2024-09-15T17:44:34+00:00 Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate Sheridan, Peter P. Brenchley, Jean E. 2000 http://dx.doi.org/10.1128/aem.66.6.2438-2444.2000 https://journals.asm.org/doi/pdf/10.1128/AEM.66.6.2438-2444.2000 en eng American Society for Microbiology https://journals.asm.org/non-commercial-tdm-license Applied and Environmental Microbiology volume 66, issue 6, page 2438-2444 ISSN 0099-2240 1098-5336 journal-article 2000 crasmicro https://doi.org/10.1128/aem.66.6.2438-2444.2000 2024-08-12T04:06:18Z ABSTRACT We isolated a gram-positive, halotolerant psychrophile from a hypersaline pond located on the McMurdo Ice Shelf in Antarctica. A phylogenetic analysis of the 16S rRNA gene sequence of this organism showed that it is a member of the genus Planococcus . This assignment is consistent with the morphology and physiological characteristics of the organism. A gene encoding a β-galactosidase in this isolate was cloned in an Escherichia coli host. Sequence analysis of this gene placed it in glycosidase family 42 most closely related to an enzyme from Bacillus circulans . Even though an increasing number of family 42 glycosidase sequences are appearing in databases, little information about the biochemical features of these enzymes is available. Therefore, we purified and characterized this enzyme. The purified enzyme did not appear to have any metal requirement, had an optimum pH of 6.5 and an optimum temperature of activity at 42°C, and was irreversibly inactivated within 10 min when it was incubated at 55°C. The enzyme had an apparent K m of 4.9 μmol of o -nitrophenyl-β- d -galactopyranoside, and the V max was 467 μmol of o -nitrophenol produced/min/mg of protein at 39°C. Of special interest was the finding that the enzyme remained active at high salt concentrations, which makes it a possible reporter enzyme for halotolerant and halophilic organisms. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf ASM Journals (American Society for Microbiology) Applied and Environmental Microbiology 66 6 2438 2444 |
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Open Polar |
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ASM Journals (American Society for Microbiology) |
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crasmicro |
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English |
description |
ABSTRACT We isolated a gram-positive, halotolerant psychrophile from a hypersaline pond located on the McMurdo Ice Shelf in Antarctica. A phylogenetic analysis of the 16S rRNA gene sequence of this organism showed that it is a member of the genus Planococcus . This assignment is consistent with the morphology and physiological characteristics of the organism. A gene encoding a β-galactosidase in this isolate was cloned in an Escherichia coli host. Sequence analysis of this gene placed it in glycosidase family 42 most closely related to an enzyme from Bacillus circulans . Even though an increasing number of family 42 glycosidase sequences are appearing in databases, little information about the biochemical features of these enzymes is available. Therefore, we purified and characterized this enzyme. The purified enzyme did not appear to have any metal requirement, had an optimum pH of 6.5 and an optimum temperature of activity at 42°C, and was irreversibly inactivated within 10 min when it was incubated at 55°C. The enzyme had an apparent K m of 4.9 μmol of o -nitrophenyl-β- d -galactopyranoside, and the V max was 467 μmol of o -nitrophenol produced/min/mg of protein at 39°C. Of special interest was the finding that the enzyme remained active at high salt concentrations, which makes it a possible reporter enzyme for halotolerant and halophilic organisms. |
format |
Article in Journal/Newspaper |
author |
Sheridan, Peter P. Brenchley, Jean E. |
spellingShingle |
Sheridan, Peter P. Brenchley, Jean E. Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
author_facet |
Sheridan, Peter P. Brenchley, Jean E. |
author_sort |
Sheridan, Peter P. |
title |
Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
title_short |
Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
title_full |
Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
title_fullStr |
Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
title_full_unstemmed |
Characterization of a Salt-Tolerant Family 42 β-Galactosidase from a Psychrophilic Antarctic Planococcus Isolate |
title_sort |
characterization of a salt-tolerant family 42 β-galactosidase from a psychrophilic antarctic planococcus isolate |
publisher |
American Society for Microbiology |
publishDate |
2000 |
url |
http://dx.doi.org/10.1128/aem.66.6.2438-2444.2000 https://journals.asm.org/doi/pdf/10.1128/AEM.66.6.2438-2444.2000 |
genre |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf |
op_source |
Applied and Environmental Microbiology volume 66, issue 6, page 2438-2444 ISSN 0099-2240 1098-5336 |
op_rights |
https://journals.asm.org/non-commercial-tdm-license |
op_doi |
https://doi.org/10.1128/aem.66.6.2438-2444.2000 |
container_title |
Applied and Environmental Microbiology |
container_volume |
66 |
container_issue |
6 |
container_start_page |
2438 |
op_container_end_page |
2444 |
_version_ |
1810492201548906496 |