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| == Function == | | == Function == |
| [https://www.uniprot.org/uniprot/Q587A7_TRYB2 Q587A7_TRYB2] | | [https://www.uniprot.org/uniprot/Q587A7_TRYB2 Q587A7_TRYB2] |
| <div style="background-color:#fffaf0;">
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| == Publication Abstract from PubMed ==
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| Catalytically inactive enzyme paralogs occur in many genomes. Some regulate their active counterparts but the structural principles of this regulation remain largely unknown. We report X-ray structures of Trypanosoma brucei S-adenosylmethionine decarboxylase alone and in functional complex with its catalytically dead paralogous partner, prozyme. We show monomeric TbAdoMetDC is inactive because of autoinhibition by its N-terminal sequence. Heterodimerization with prozyme displaces this sequence from the active site through a complex mechanism involving a cis-to-trans proline isomerization, reorganization of a beta-sheet, and insertion of the N-terminal alpha-helix into the heterodimer interface, leading to enzyme activation. We propose that the evolution of this intricate regulatory mechanism was facilitated by the acquisition of the dimerization domain, a single step that can in principle account for the divergence of regulatory schemes in the AdoMetDC enzyme family. These studies elucidate an allosteric mechanism in an enzyme and a plausible scheme by which such complex cooperativity evolved.
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| Relief of autoinhibition by conformational switch explains enzyme activation by a catalytically dead paralog.,Volkov OA, Kinch L, Ariagno C, Deng X, Zhong S, Grishin N, Tomchick DR, Chen Z, Phillips MA Elife. 2016 Dec 15;5. pii: e20198. doi: 10.7554/eLife.20198. PMID:27977001<ref>PMID:27977001</ref>
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| From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| </div>
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| <div class="pdbe-citations 5tvo" style="background-color:#fffaf0;"></div>
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| ==See Also== | | ==See Also== |
| *[[SAM decarboxylase|SAM decarboxylase]] | | *[[SAM decarboxylase|SAM decarboxylase]] |
| == References ==
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| <references/>
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| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
