Expression of calmodulin-binding domain of neuronal nitric synthase and its binding activity to calmodulin

To facilitate the study of associations of nNOS functions with its calmodulin (CaM) binding domain and to prepare nNOS specific inhibiting peptides from phage peptide library, we have amplified the coding gene of nNOS CaM-binding domain (nNOS 2544-2988 bp) and expressed it in E.coli. The recombinant product in the size of 22 kDa was purified (over 90% in pure) by His.Tag-Sepharose column and its obvious CaM-binding activity was detected with CaM overlay assay. Since it possesses the sequence specificity and effective calmodulin-binding activity, the protein was considered an ideal target for screening nNOS specific peptides from peptide library and also an antigen for marking nNOS antibody.