Characterization of the Catalytic Domain of Human APOBEC3B and the Critical Structural Role for a Conserved Methionine.

ABSTRACT: Human APOBEC3B deaminates cytosines in DNA and belongs to the AID/APOBEC family of enzymes. These proteins are involved in innate and adaptive immunity and may cause mutations in a variety of cancers. To characterize its ability to convert cytosines into uracils, we tested several derivatives of APOBEC3B gene for their ability to cause mutations in Escherichia coli. Through this analysis, a methionine residue at the junction of the amino-terminal domain (NTD) and the carboxy-terminal domain (CTD) was found to be essential for high mutagenicity. Properties of mutants with substitutions at this position, examination of existing molecular structures of APOBEC3 family members and molecular modeling suggest that this residue is essential for the structural stability of this family of proteins.

SUBMITTER: Siriwardena SU 

PROVIDER: S-EPMC4579057 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature