The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements.
Acetohydroxyacid synthase (AHAS) catalyzes the first step of branched-chain amino acid biosynthesis, a pathway essential to the life-cycle of plants and micro-organisms. The catalytic subunit has thiamin diphosphate (ThDP) and flavin adenine dinucleotide (FAD) as indispensable co-factors. A new, hig...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2017-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC5298238?pdf=render |
| _version_ | 1818305700214865920 |
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| author | Thierry Lonhienne Mario D Garcia James A Fraser Craig M Williams Luke W Guddat |
| author_facet | Thierry Lonhienne Mario D Garcia James A Fraser Craig M Williams Luke W Guddat |
| author_sort | Thierry Lonhienne |
| collection | DOAJ |
| description | Acetohydroxyacid synthase (AHAS) catalyzes the first step of branched-chain amino acid biosynthesis, a pathway essential to the life-cycle of plants and micro-organisms. The catalytic subunit has thiamin diphosphate (ThDP) and flavin adenine dinucleotide (FAD) as indispensable co-factors. A new, high resolution, 2.0 Å crystal structure of Saccharomyces cerevisiae AHAS reveals that the dimer is asymmetric, with the catalytic centres having distinct structures where FAD is trapped in two different conformations indicative of different redox states. Two molecules of oxygen (O2) are bound on the surface of each active site and a tunnel in the polypeptide appears to passage O2 to the active site independently of the substrate. Thus, O2 appears to play a novel "co-factor" role in this enzyme. We discuss the functional implications of these features of the enzyme that have not previously been described. |
| first_indexed | 2024-12-13T06:30:45Z |
| format | Article |
| id | doaj.art-8461101fa8174e05a8fe860c0e127821 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-13T06:30:45Z |
| publishDate | 2017-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-8461101fa8174e05a8fe860c0e1278212022-12-21T23:56:37ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01122e017144310.1371/journal.pone.0171443The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements.Thierry LonhienneMario D GarciaJames A FraserCraig M WilliamsLuke W GuddatAcetohydroxyacid synthase (AHAS) catalyzes the first step of branched-chain amino acid biosynthesis, a pathway essential to the life-cycle of plants and micro-organisms. The catalytic subunit has thiamin diphosphate (ThDP) and flavin adenine dinucleotide (FAD) as indispensable co-factors. A new, high resolution, 2.0 Å crystal structure of Saccharomyces cerevisiae AHAS reveals that the dimer is asymmetric, with the catalytic centres having distinct structures where FAD is trapped in two different conformations indicative of different redox states. Two molecules of oxygen (O2) are bound on the surface of each active site and a tunnel in the polypeptide appears to passage O2 to the active site independently of the substrate. Thus, O2 appears to play a novel "co-factor" role in this enzyme. We discuss the functional implications of these features of the enzyme that have not previously been described.http://europepmc.org/articles/PMC5298238?pdf=render |
| spellingShingle | Thierry Lonhienne Mario D Garcia James A Fraser Craig M Williams Luke W Guddat The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. PLoS ONE |
| title | The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. |
| title_full | The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. |
| title_fullStr | The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. |
| title_full_unstemmed | The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. |
| title_short | The 2.0 Å X-ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements. |
| title_sort | 2 0 a x ray structure for yeast acetohydroxyacid synthase provides new insights into its cofactor and quaternary structure requirements |
| url | http://europepmc.org/articles/PMC5298238?pdf=render |
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