Flp Ribonuclease Activities

摘要: Abstract The ribonuclease active site harbored by the Flp site-specific recombinase can act on two neighboring phosphodiester bonds to yield mechanistically distinct chain breakage reactions. One of RNase reactions apparently proceeds via a covalent enzyme intermediate and targets position involved in DNA recombination (Flp I activity). second activity II) immediately 3′ side but appears not involve an enzyme-linked intermediate. is absolutely dependent upon Tyr-343 competitive with respect normal strand joining reaction. It utilize 2′-hydroxyl group from any one four ribonucleotides comparable efficiencies cleavage On other hand, II reaction mediated Flp(Y343F) specific for U cannot ribo-A, -G, or -C under standard conditions. also sensitive 3′-neighboring base. Although dT functional, stimulated U-2′-OMe. effectively competes Tyr-343, even though their are same.