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Thermophilic DNases, RNases and Proteases

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry".

Deadline for manuscript submissions: closed (25 January 2014) | Viewed by 19497

Special Issue Editor

Department of Food Science, University of Massachusetts Amherst, 228 Chenoweth Laboratory, 100 Holdsworth Way, Amherst, MA 01003, USA
Interests: bacteriophage infectious for refrigerated food spoilage bacteria; fishery microbiology; characterization of microbial proteases and DNases; immunological identification of food borne bacterial pathogens; fermentation technology; production of paralytic shellfish toxins by dinoflagellated algae; production of fish silage and fish hydrolysates; detection of carcinogens in foods; quantitative real-time PCR detection of bacterial pathogenic bacteria in foods

Special Issue Information

Dear Colleagues,

Thermophilic enzymes can be defined as enzymes that are optimally functional at temperatures near or above 45 °C and exhibit little or no enzyme activity at 20 °C. Thermophilic enzymes have a number of unique uses and can also create certain biochemical problems. Nucleases are usually the enemy of the molecular biologist who is involved in preserving the integrity of RNA or DNA samples. However, DNases and RNases do have certain indispensable roles in molecular biology laboratories. Common applications of DNases are: (1) elimination of trace quantities of DNA from glassware, (2) eliminating DNA from RNA preparations, (3) analyzing DNA-protein interactions via DNase footprinting, and (4) nicking DNA prior to radiolabelling by nick translation. In addition, a DNase is now used in the treatment of cystic fibrosis to reduce the viscosity of lung fluids. Ribonucleases are used for (1) eliminating or reducing RNA contamination in plasmid DNA preparations, (2) and mapping mutations in DNA:RNA hybrids by mismatch cleavage at sites of single base mismatches, allowing analysis of cleavage products.  The thermal DNase activity present in shellfish tissue can constitute a major problem in PCR detection of bacterial pathogens in shellfish.  Recent studies indicate that a thermophilic DNase is capable of notably reducing biofilms produced by Listeria monocytogenes.

Proteases have wide industrial application.  Heat tolerant alkaline proteases are commonly added to laundry detergents. The tanning industry uses proteases for dehairing and bating (softening) leather hides. Proteinase K continues to be widely used to digest the peptidogycan of Gram-positive cells to facilitate cell lysis and release of DNA. Proteases are frequently used as meat tenderizers. The ideal meat tenderizing protease should retain some activity during the initial cooking stages so as to reduce the total digestion time.

It is estimated that less than 1% of thermophiic DNases, RNases and proteases produced by microorganisms native to hot springs and oceanic thermal vents have been identified and characterized. In addition, there is a scarcity of data describing thermophilic DNases and RNases from microorganisms in compost heaps. This special issue is designed to elucidate recent studies dealing with thermophilic DNases, RNases and proteases.

Dr. Robert E. Levin
Guest Editor

Submission

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed Open Access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF.


Keywords

  • Thermophilic enzymes
  • RNases
  • DNases
  • Proteases
  • hot springs
  • thermal vents
  • compost heaps
  • meat tenderizing proteases
  • leather bating proteases
  • shellfish DNase

Published Papers (3 papers)

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859 KiB  
Article
A New Pepstatin-Insensitive Thermopsin-Like Protease Overproduced in Peptide-Rich Cultures of Sulfolobus solfataricus
by Marta Gogliettino, Alessia Riccio, Ennio Cocca, Mosè Rossi, Gianna Palmieri and Marco Balestrieri
Int. J. Mol. Sci. 2014, 15(2), 3204-3219; https://doi.org/10.3390/ijms15023204 - 21 Feb 2014
Cited by 11 | Viewed by 6147
Abstract
In this study, we gain insight into the extracellular proteolytic system of Sulfolobus solfataricus grown on proteinaceous substrates, providing further evidence that acidic proteases were specifically produced in response to peptide-rich media. The main proteolytic component was the previously isolated SsMTP (Sulfolobus [...] Read more.
In this study, we gain insight into the extracellular proteolytic system of Sulfolobus solfataricus grown on proteinaceous substrates, providing further evidence that acidic proteases were specifically produced in response to peptide-rich media. The main proteolytic component was the previously isolated SsMTP (Sulfolobus solfataricus multi-domain thermopsin-like protease), while the less abundant (named SsMTP-1) one was purified, characterized and identified as the sso1175 gene-product. The protein revealed a multi-domain organization shared with the cognate SsMTP with a catalytic domain followed by several tandemly-repeated motifs. Moreover, both enzymes were found spread across the Crenarchaeota phylum and belonging to the thermopsin family, although segregated into diverse phylogenetic clusters. SsMTP-1 showed a 75-kDa molecular mass and was stable in the temperature range 50–90 °C, with optimal activity at 70 °C and pH 2.0. Serine, metallo and aspartic protease inhibitors did not affect the enzyme activity, designating SsMTP-1 as a new member of the pepstatin-insensitive aspartic protease family. The peptide-bond-specificity of SsMTP-1 in the cleavage of the oxidized insulin B chain was uncommon amongst thermopsins, suggesting that it could play a distinct, but cooperative role in the protein degradation machinery. Interestingly, predictions of the transmembrane protein topology of SsMTP and SsMTP-1 strongly suggest a possible contribution in signal-transduction pathways. Full article
(This article belongs to the Special Issue Thermophilic DNases, RNases and Proteases)
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832 KiB  
Article
Purification of an Inducible DNase from a Thermophilic Fungus
by Kyle S. Landry, Andrea Vu and Robert E. Levin
Int. J. Mol. Sci. 2014, 15(1), 1300-1314; https://doi.org/10.3390/ijms15011300 - 20 Jan 2014
Cited by 3 | Viewed by 6397
Abstract
The ability to induce an extracellular DNase from a novel thermophilic fungus was studied and the DNAse purified using both traditional and innovative purification techniques. The isolate produced sterile hyphae under all attempted growing conditions, with an average diameter of 2 µm and [...] Read more.
The ability to induce an extracellular DNase from a novel thermophilic fungus was studied and the DNAse purified using both traditional and innovative purification techniques. The isolate produced sterile hyphae under all attempted growing conditions, with an average diameter of 2 µm and was found to have an optimal temperature of 45 °C and a maximum of 65 °C. Sequencing of the internal transcribed region resulted in a 91% match with Chaetomium sp., suggesting a new species, but further clarification on this point is needed. The optimal temperature for DNase production was found to be 55 °C and was induced by the presence of DNA and/or deoxyribose. Static growth of the organism resulted in significantly higher DNase production than agitated growth. The DNase was purified 145-fold using a novel affinity membrane purification system with 25% of the initial enzyme activity remaining. Electrophoresis of the purified enzyme resulted in a single protein band, indicating DNase homogeneity. Full article
(This article belongs to the Special Issue Thermophilic DNases, RNases and Proteases)
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922 KiB  
Article
Purification and Characterization of Iso-Ribonucleases from a Novel Thermophilic Fungus
by Kyle S. Landry and Robert E. Levin
Int. J. Mol. Sci. 2014, 15(1), 944-957; https://doi.org/10.3390/ijms15010944 - 10 Jan 2014
Cited by 5 | Viewed by 6542
Abstract
A thermophilic fungus previously isolated from composted horse manure was found to produce extracellular iso-RNases that were purified 127.6-fold using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined electrophoretically using 4%–15% gradient [...] Read more.
A thermophilic fungus previously isolated from composted horse manure was found to produce extracellular iso-RNases that were purified 127.6-fold using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined electrophoretically using 4%–15% gradient polyacrylamide gels. RNase activity was dependent on the presence of a metal co-factor with significantly more activity with Zn2+ or Mn2+ than Mg2+. The RNases exhibited maximum activity at both pH 3.0 and pH 7.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the iso-RNase was 70 °C. The molecular weight of the iso-RNase was determined to be 69 kDa using a Sephadex G-75 column. Full article
(This article belongs to the Special Issue Thermophilic DNases, RNases and Proteases)
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