Structural characterization and biochemical analysis of ID2, an inhibitor of DNA binding

The ID proteins, a class of transcription regulators, were named for their role as inhibitors of DNA-binding and differentiation. They contained a helix-loop-helix (HLH) domain without a basic DNA-binding domain and functioned through dimerization with basic-HLH transcription factors to inactivate their DNA-binding abilities. ID2, a member of the ID family was cloned, expressed and purified using strategies to overcome the known instability of this protein both in vitro and in vivo. The crystal structure of ID2 was solved to 2.1 ? and showed for the first time, a loop ion that was previously unreported in HLH structures. Key residues based on the structural analysis of ID2 were identified and mutated to gauge their importance in the dimerization of the ID protein family through competitive electrophoretic mobility shift assays.

Author dc:creator

• MARIE VIVIAN WONG TZU YENN

• ID2, inhibitor of dna-binding, HLH, loop, ion, crystal