Comparative analysis of the secondary structural motifs of P450BM-3 and the regions located upstream of the calmodulin-binding domain in the nitric oxide synthases.
Uvarov VYu, Lyashenko Aa, Zimin Ag · PubMed · 1996
The proposed method of multiple alignment of secondary structures makes it possible to estimate the multidomain enzymes' structural similarity in those cases where, following alignment, the identity appears to be inadequate or too insignificant to estimate protein relationship in spite of their functional analogy. Multiple alignment of sequences, representing the secondary structural elements of the nitric oxide synthase (NOS) N-terminal "tails", localized upstream of the calmodulin (CAM)-binding domain, and the P450 superfamily representative P450BM-3 has revealed the existence of a common secondary structural motif, standing of 60% identity between the polypeptide chain packing of NOS and the full sequence of P450BM3. This fact may point to the existence of their common ancestor. Presence of the linker olygopeptides within NOS permitted us to determine the boundary of the cytochrome-like part of NOS.