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Chinese hamster AP endonuclease operates by a two‐metal ion assisted catalytic mechanism
Author(s) -
Borjigin Mandula,
Arenaz Pablo,
Stec Boguslaw
Publication year - 2012
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/j.febslet.2011.12.025
Subject(s) - endonuclease , metal ions in aqueous solution , catalysis , chemistry , metal , enzyme , titration , hamster , dna , substrate (aquarium) , ion , stereochemistry , biochemistry , inorganic chemistry , microbiology and biotechnology , biology , organic chemistry , ecology
The APE1, an important mammalian AP endonuclease, is an essential enzyme in the base excision DNA repair pathway (BER). The number of metal ions involved directly in the catalysis remains controversial. Here we describe the metal ion titration experiments that demonstrate the requirement for two metal ions for the endonuclease activity of the Chinese hamster APE1. The titration with the non‐activating metal ion La 3+ showed a biphasic behavior with activating and inhibitory effects of La 3+ in the range of 0–100 μM in the presence of 5 mM Mg 2+ . Modeling of the enzyme‐substrate/product complexes provided insight into the endonuclease activity and elucidated the nature of the crystal structures. Accordingly, we proposed a reaction scheme for the two‐metal ion assisted catalysis of chAPE1 endonuclease activity.