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Cleavage experiments with deoxythymidine 3′,5′‐bis‐( p ‐nitrophenyl phosphate) suggest that the homing endonuclease I‐ Ppo I follows the same mechanism of phosphodiester bond hydrolysis as the non‐specific Serratia nuclease 1
Author(s) -
Friedhoff Peter,
Franke Ingo,
Krause Kurt L,
Pingoud Alfred
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01660-3
Subject(s) - phosphodiester bond , homing endonuclease , cleavage (geology) , chemistry , phosphate , hydrolysis , stereochemistry , endonuclease , biochemistry , bond cleavage , enzyme , biology , rna , paleontology , fracture (geology) , gene , catalysis
We show here that two nucleases, Serratia nuclease and I‐ Ppo I, with contrasting specificities, i.e. non‐specific vs. highly sequence specific, share a structurally similar active site region with conservation of the catalytically relevant histidine and asparagine residues. On the basis of a comparison of the available structures and biochemical data for wild type and mutant variants of Serratia nuclease and I‐ Ppo I we propose that both enzymes have a common catalytic mechanism, a proposition that is supported by our finding that both enzymes accept deoxythymidine 3′,5′‐bis‐( p ‐nitrophenyl phosphate) as a substrate and cleave it in an identical manner. According to this mechanism a histidine residue functions as a general base and Mg 2+ bound to an asparagine residue as a Lewis acid in phosphodiester bond cleavage.