Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i>
Methionine sulfoxide reductase (Msr) is a family of enzymes that reduces oxidized methionine and plays an important role in the survival of bacteria under oxidative stress conditions. MsrA and MsrB exist in a fusion protein form (MsrAB) in some pathogenic bacteria, such as <i>Helicobacter pylo...
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MDPI AG
2021-03-01
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| Series: | Antioxidants |
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| author | Sulhee Kim Kitaik Lee Sun-Ha Park Geun-Hee Kwak Min Seok Kim Hwa-Young Kim Kwang Yeon Hwang |
| author_facet | Sulhee Kim Kitaik Lee Sun-Ha Park Geun-Hee Kwak Min Seok Kim Hwa-Young Kim Kwang Yeon Hwang |
| author_sort | Sulhee Kim |
| collection | DOAJ |
| description | Methionine sulfoxide reductase (Msr) is a family of enzymes that reduces oxidized methionine and plays an important role in the survival of bacteria under oxidative stress conditions. MsrA and MsrB exist in a fusion protein form (MsrAB) in some pathogenic bacteria, such as <i>Helicobacter pylori</i> (<i>Hp</i>), <i>Streptococcus pneumoniae</i>, and <i>Treponema denticola</i>. To understand the fused form instead of the separated enzyme at the molecular level, we determined the crystal structure of <i>Hp</i>MsrAB<sup>C44S/C318S</sup> at 2.2 Å, which showed that a linker region (<i>Hpiloop</i>, 193–205) between two domains interacted with each <i>Hp</i>MsrA or <i>Hp</i>MsrB domain via three salt bridges (E193-K107, D197-R103, and K200-D339). Two acetate molecules in the active site pocket showed an <i>sp</i><sup>2</sup> planar electron density map in the crystal structure, which interacted with the conserved residues in fusion MsrABs from the pathogen. Biochemical and kinetic analyses revealed that <i>Hpiloop</i> is required to increase the catalytic efficiency of <i>Hp</i>MsrAB. Two salt bridge mutants (D193A and E199A) were located at the entrance or tailgate of <i>Hpiloop</i>. Therefore, the linker region of the MsrAB fusion enzyme plays a key role in the structural stability and catalytic efficiency and provides a better understanding of why MsrAB exists in a fused form. |
| first_indexed | 2024-03-09T05:24:03Z |
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| issn | 2076-3921 |
| language | English |
| last_indexed | 2024-03-09T05:24:03Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
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| series | Antioxidants |
| spelling | doaj.art-2b320b97dc9941269551f855999a37e12023-12-03T12:38:23ZengMDPI AGAntioxidants2076-39212021-03-0110338910.3390/antiox10030389Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i>Sulhee Kim0Kitaik Lee1Sun-Ha Park2Geun-Hee Kwak3Min Seok Kim4Hwa-Young Kim5Kwang Yeon Hwang6Department of Biotechnology, Korea University, Seoul 02841, KoreaDepartment of Biotechnology, Korea University, Seoul 02841, KoreaDepartment of Biotechnology, Korea University, Seoul 02841, KoreaDepartment of Biochemistry and Molecular Biology, Yeungnam University College of Medicine, Daegu 42415, KoreaDepartment of Biotechnology, Korea University, Seoul 02841, KoreaDepartment of Biochemistry and Molecular Biology, Yeungnam University College of Medicine, Daegu 42415, KoreaDepartment of Biotechnology, Korea University, Seoul 02841, KoreaMethionine sulfoxide reductase (Msr) is a family of enzymes that reduces oxidized methionine and plays an important role in the survival of bacteria under oxidative stress conditions. MsrA and MsrB exist in a fusion protein form (MsrAB) in some pathogenic bacteria, such as <i>Helicobacter pylori</i> (<i>Hp</i>), <i>Streptococcus pneumoniae</i>, and <i>Treponema denticola</i>. To understand the fused form instead of the separated enzyme at the molecular level, we determined the crystal structure of <i>Hp</i>MsrAB<sup>C44S/C318S</sup> at 2.2 Å, which showed that a linker region (<i>Hpiloop</i>, 193–205) between two domains interacted with each <i>Hp</i>MsrA or <i>Hp</i>MsrB domain via three salt bridges (E193-K107, D197-R103, and K200-D339). Two acetate molecules in the active site pocket showed an <i>sp</i><sup>2</sup> planar electron density map in the crystal structure, which interacted with the conserved residues in fusion MsrABs from the pathogen. Biochemical and kinetic analyses revealed that <i>Hpiloop</i> is required to increase the catalytic efficiency of <i>Hp</i>MsrAB. Two salt bridge mutants (D193A and E199A) were located at the entrance or tailgate of <i>Hpiloop</i>. Therefore, the linker region of the MsrAB fusion enzyme plays a key role in the structural stability and catalytic efficiency and provides a better understanding of why MsrAB exists in a fused form.https://www.mdpi.com/2076-3921/10/3/389MsrABfusion proteinlinker regioncatalytic efficiency |
| spellingShingle | Sulhee Kim Kitaik Lee Sun-Ha Park Geun-Hee Kwak Min Seok Kim Hwa-Young Kim Kwang Yeon Hwang Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> Antioxidants MsrAB fusion protein linker region catalytic efficiency |
| title | Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> |
| title_full | Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> |
| title_fullStr | Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> |
| title_full_unstemmed | Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> |
| title_short | Structural Insights into a Bifunctional Peptide Methionine Sulfoxide Reductase MsrA/B Fusion Protein from <i>Helicobacter pylori</i> |
| title_sort | structural insights into a bifunctional peptide methionine sulfoxide reductase msra b fusion protein from i helicobacter pylori i |
| topic | MsrAB fusion protein linker region catalytic efficiency |
| url | https://www.mdpi.com/2076-3921/10/3/389 |
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