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| == Function == | | == Function == |
| [https://www.uniprot.org/uniprot/PPO1_PHYPO PPO1_PHYPO] Mediates the homing of a group I intron in the ribosomal DNA. Makes a four-base staggered cut in its ribosomal DNA target sequence. | | [https://www.uniprot.org/uniprot/PPO1_PHYPO PPO1_PHYPO] Mediates the homing of a group I intron in the ribosomal DNA. Makes a four-base staggered cut in its ribosomal DNA target sequence. |
| <div style="background-color:#fffaf0;">
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| == Publication Abstract from PubMed ==
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| A novel mechanism of DNA endonucleolytic cleavage has been visualized for the homing endonuclease I-PpoI by trapping the uncleaved enzyme-substrate complex and comparing it to the previously visualized product complex. This enzyme employs a unique single metal mechanism. A magnesium ion is coordinated by an asparagine residue and two DNA oxygen atoms and stabilizes the phosphoanion transition state and the 3'oxygen leaving group. A hydrolytic water molecule is activated by a histidine residue for an in-line attack on the scissile phosphate. A strained enzyme-substrate-metal complex is formed before cleavage, then relaxed during the reaction.
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| A novel endonuclease mechanism directly visualized for I-PpoI.,Galburt EA, Chevalier B, Tang W, Jurica MS, Flick KE, Monnat RJ Jr, Stoddard BL Nat Struct Biol. 1999 Dec;6(12):1096-9. PMID:10581547<ref>PMID:10581547</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 1cyq" style="background-color:#fffaf0;"></div>
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| ==See Also== | | ==See Also== |
| *[[Endonuclease 3D structures|Endonuclease 3D structures]] | | *[[Endonuclease 3D structures|Endonuclease 3D structures]] |
| == References ==
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| <references/>
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| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
