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Entry M0185    4.2.99.18    DNA-(apurinic or apyrimidinic site) lyase

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Step 02

The conjugate base of 8-oxoguanine deprotonates the covalently bound Lys249.

GIF of Reaction Step M0185.stg02


Comment: The catalytic base in this reaction has been identified as the oxoguanine nucleobase. This has been demonstrated by use of base analogues and quantitative kinetic analysis, as well as time course borohydride-trapping assays. Crystal structures and modelling studies of the borohydride-trapped intermediate also demonstrated that the nucleobase was appropriately positioned to act as the catalytic base [2].



Mechanisms

Proton Transfer

Mechanism Components

Bond Formation
Bond Cleavage
Intermediate Formation

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Lys249 Side Chain reactant Covalently Attached
Hydrogen Bond Donor
Proton Donor
Asp268 Side Chain spectator Not Active

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
N-H
N-H
None
H
N

View similar reactions in MACiE.


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