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The Sulfur Oxygenase Reductase from the Mesophilic Bacterium Halothiobacillus neapolitanus is a Highly Active Thermozyme.

Veith, Andreas and Botelho, Hugo M. and Kindinger, Florian and Gomes, Cláudio M. and Kletzin, Arnulf (2012):
The Sulfur Oxygenase Reductase from the Mesophilic Bacterium Halothiobacillus neapolitanus is a Highly Active Thermozyme.
In: Journal of bacteriology, pp. 677-685, 194, (3), ISSN 1098-5530,
[Article]

Abstract

A biochemical, biophysical and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic Gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from Escherichia coli after heterologous gene expression had a temperature range of activity of 10-99°C with an optimum at 80°C (42 U/mg protein). Sulfite, thiosulfate and hydrogen sulfide were formed at varying stoichiometries in a range between pH 5.4 and 11 (optimum pH 8.4). CD spectroscopy and dynamic light scattering showed that the HnSOR adopts similar secondary and quaternary structures as the 24-subunit enzyme from the hyperthermophile Acidianus ambivalens (AaSOR). The melting point of the HnSOR was ≈20°C lower compared to the AaSOR, when analyzed with CD-monitored thermal unfolding. Homology modeling showed that the secondary structure elements of single subunit are conserved. Subtle changes in the pores of the outer shell and increased flexibility might contribute to activity at low temperature. We concluded that the thermostability was the result of a rigid protein core together with the stabilizing effect of the 24-subunit hollow sphere.

Item Type: Article
Erschienen: 2012
Creators: Veith, Andreas and Botelho, Hugo M. and Kindinger, Florian and Gomes, Cláudio M. and Kletzin, Arnulf
Title: The Sulfur Oxygenase Reductase from the Mesophilic Bacterium Halothiobacillus neapolitanus is a Highly Active Thermozyme.
Language: English
Abstract:

A biochemical, biophysical and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic Gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from Escherichia coli after heterologous gene expression had a temperature range of activity of 10-99°C with an optimum at 80°C (42 U/mg protein). Sulfite, thiosulfate and hydrogen sulfide were formed at varying stoichiometries in a range between pH 5.4 and 11 (optimum pH 8.4). CD spectroscopy and dynamic light scattering showed that the HnSOR adopts similar secondary and quaternary structures as the 24-subunit enzyme from the hyperthermophile Acidianus ambivalens (AaSOR). The melting point of the HnSOR was ≈20°C lower compared to the AaSOR, when analyzed with CD-monitored thermal unfolding. Homology modeling showed that the secondary structure elements of single subunit are conserved. Subtle changes in the pores of the outer shell and increased flexibility might contribute to activity at low temperature. We concluded that the thermostability was the result of a rigid protein core together with the stabilizing effect of the 24-subunit hollow sphere.

Journal or Publication Title: Journal of bacteriology
Volume: 194
Number: 3
Divisions: 10 Department of Biology > Sulfur Biochemistry and Microbial Bioenergetics
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10 Department of Biology
Date Deposited: 13 Dec 2011 09:13
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