Rep-Type endonuclease
Enzymatic reaction: All rep-type endonuclease belongs to the HUH-endonuclease superfamily. There are three class: Cress-type (Cressdnaviricota and Alphasatellitidae), Parvo -type (Piccovirales) and prokaryotic-type (Tubulavirales)
- Tyr-endonuclease
Domain: Cress-type PFAM: PF02407 Gemini-type PFAM Parvo-type PFAM: PF01057 Ino-type PFAM: PF05144 Micro-type PFAM: PF05840
Mechanism : The active site consists of an Tyrosine, a triad HUH or HUG (Histidine, hydrophobic, Histidine/Glutamine) and a Mg+ ion. The Tyr acts as a nucleophile and attacks the Phosphate atom of ssDNA strand at the top of an hairpin, while the mg+ ion assists the process by stabilizing the reaction intermediates. The result releases a 3'OH ssDNA strand, while the the other 5'Phosphate strand remains bound to the protein.