Expression and Structural Studies of Nucleic Acid Binding Cytidine Deaminases

Activation Induced Deaminase (AID) and the APOBEC3 proteins are nucleic acid cytidine deaminases (CDs) which play critical roles the immune system. These proteins bind both single-stranded -DNA (ssDNA) and -RNA (ssRNA) and catalyze deamination of ssDNA cytidines, the mechanisms mediating said binding events are poorly understood and their study has proven troublesome due to the difficulty of working with these proteins. Due to a lack of success in using AID in biochemical and structural analyses we turned to another CD, the Brassica oleacra var. capitate cytidine deaminase putative tRNA CD (BOCD). BOCD was selected due to predicted structural homology to other nucleic acid binding CDs and its immune functioning. I have determined the structure of BOCD crystallographically and analyzed it against other CD structures. BOCD will be useful for studying nucleic acid interactions of CDs and may be useful for engineering of more soluble nucleic acid CDs.M.Sc