Zinc enhancement of cytidine deaminase activity highlights a potential allosteric role of loop-3 in regulating APOBEC3 enzymes
OPEN Scientific reports | 19 Dec 2015
A Marx, M Galilee and A Alian
The strong association of APOBEC3 cytidine deaminases with somatic mutations leading to cancers accentuates the importance of their tight intracellular regulation to minimize cellular transformations. We reveal a novel allosteric regulatory mechanism of APOBEC3 enzymes showing that APOBEC3G and APOBEC3A coordination of a secondary zinc ion, reminiscent to ancestral deoxycytidylate deaminases, enhances deamination activity. Zinc binding is pinpointed to loop-3 which whilst highly variable harbors a catalytically essential and spatially conserved asparagine at its N-terminus. We suggest that loop-3 may play a general role in allosterically tuning the activity of zinc-dependent cytidine deaminase family members.
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