1990
DOI 10.1002/pmic.201300357
Proteomics 2014, 14, 1990–1998
RESEARCH ARTICLE
Unraveling the specificities of the different human methionine sulfoxide reductases ` 1,2∗ , Veronique Jonckheere1,2 , Kris Gevaert1,2 Elien Vandermarliere1,2 , Bart Ghesquiere and Lennart Martens1,2 1 2
Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
The oxidation of free and protein-bound methionine into methionine sulfoxide is a frequently occurring modification caused by ROS. Most organisms express methionine sulfoxide reductases (MSR enzymes) to repair this potentially damaging modification. Humans express three different MSRB enzymes which reside in different cellular compartments. In this study, we have explored the specificity of the human MSRB enzymes both by in silico modeling and by experiments on oxidized peptides. We found that MSRB1 is the least specific MSRB enzyme, which is in agreement with the observation that MSRB1 is the only MSRB enzyme found in the cytosol and the nucleus, and therefore requires a broad specificity to reduce all possible substrates. MSRB2 and MSRB3, which are both found in mitochondria, are more specific but because of their co-occurrence they can likely repair all possible substrates.
Received: August 14, 2013 Revised: February 4, 2014 Accepted: April 8, 2014
Keywords: In silico analysis / Methionine sulfoxide reductase / Oxidized methionine / Specificity / Technology
1
Additional supporting information may be found in the online version of this article at the publisher’s web-site
Introduction
ROS such as the superoxide anion (O2 _ ), hydroxyl radicals (HO), hydrogen peroxide (H2 O2 ), and singlet oxygens (1 O2 ) are generated in aerobic organisms as products or by-products of mitochondrial respiration and other metabolic processes and enzymes such as oxidoreductases [1]. Due to their high reactivity they can modify proteins, lipids, and DNA. This modification might result in functional alterations of these macromolecules and is often related to disease and accelerated aging [2]. Several scavengers such as superoxide dismutase, catalase, and small compounds (glutathione, vitamins) have been selected for throughout evolution to eliminate Correspondence: Professor Kris Gevaert, Department of Medical Protein Research, Universiteit Gent–VIB, A. Baertsoenkaai 3, B9000 Gent, Belgium E-mail: [email protected] Fax: +32 9 264 94 96 Abbreviations: Met-SO, methionine sulfoxide; MSR, methionine sulfoxide reductases
C 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
these ROS [3, 4]. Nevertheless, damage to macromolecules is common. In proteins, Met is the residue most susceptible to oxidative modification by ROS followed by Cys [5]. Met is converted to methionine sulfoxide (Met-SO). Reversion of this modification is achieved by repair enzymes, methionine sulfoxide reductases (MSR). Sometimes (
DOI 10.1002/pmic.201300357
Proteomics 2014, 14, 1990–1998
RESEARCH ARTICLE
Unraveling the specificities of the different human methionine sulfoxide reductases ` 1,2∗ , Veronique Jonckheere1,2 , Kris Gevaert1,2 Elien Vandermarliere1,2 , Bart Ghesquiere and Lennart Martens1,2 1 2
Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
The oxidation of free and protein-bound methionine into methionine sulfoxide is a frequently occurring modification caused by ROS. Most organisms express methionine sulfoxide reductases (MSR enzymes) to repair this potentially damaging modification. Humans express three different MSRB enzymes which reside in different cellular compartments. In this study, we have explored the specificity of the human MSRB enzymes both by in silico modeling and by experiments on oxidized peptides. We found that MSRB1 is the least specific MSRB enzyme, which is in agreement with the observation that MSRB1 is the only MSRB enzyme found in the cytosol and the nucleus, and therefore requires a broad specificity to reduce all possible substrates. MSRB2 and MSRB3, which are both found in mitochondria, are more specific but because of their co-occurrence they can likely repair all possible substrates.
Received: August 14, 2013 Revised: February 4, 2014 Accepted: April 8, 2014
Keywords: In silico analysis / Methionine sulfoxide reductase / Oxidized methionine / Specificity / Technology
1
Additional supporting information may be found in the online version of this article at the publisher’s web-site
Introduction
ROS such as the superoxide anion (O2 _ ), hydroxyl radicals (HO), hydrogen peroxide (H2 O2 ), and singlet oxygens (1 O2 ) are generated in aerobic organisms as products or by-products of mitochondrial respiration and other metabolic processes and enzymes such as oxidoreductases [1]. Due to their high reactivity they can modify proteins, lipids, and DNA. This modification might result in functional alterations of these macromolecules and is often related to disease and accelerated aging [2]. Several scavengers such as superoxide dismutase, catalase, and small compounds (glutathione, vitamins) have been selected for throughout evolution to eliminate Correspondence: Professor Kris Gevaert, Department of Medical Protein Research, Universiteit Gent–VIB, A. Baertsoenkaai 3, B9000 Gent, Belgium E-mail: [email protected] Fax: +32 9 264 94 96 Abbreviations: Met-SO, methionine sulfoxide; MSR, methionine sulfoxide reductases
C 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
these ROS [3, 4]. Nevertheless, damage to macromolecules is common. In proteins, Met is the residue most susceptible to oxidative modification by ROS followed by Cys [5]. Met is converted to methionine sulfoxide (Met-SO). Reversion of this modification is achieved by repair enzymes, methionine sulfoxide reductases (MSR). Sometimes (
