view article
Figure 5
Structural comparison with other (strept)avidin family members. Left: superimposition of the overall structures of streptavidin C1, streptavidin (PDB entry 2bc3) and avidin (PDB entry 5irw). Streptavidin C1, streptavidin and avidin are represented by gray, blue and magenta ribbon models, respectively. The extension C-terminal peptide (ECP) is represented as an orange cartoon model and D-biotin is represented by a green stick model. Right: enlarged view of the ECP (amino acids 180–191), which stretches into the biotin-binding site of the same monomer. When superimposed on streptavidin, the ECP region, which is the binding site for D-biotin, reveals a similar binding site in streptavidin C1 and streptavidin. Most of the amino-acid sequence of the ECP differs from that of streptavidin, apart from the –184NP185– sequence.

IUCrJ
Volume 8| Part 2| March 2021| Pages 168-177
ISSN: 2052-2525
https://doi.org/10.1107/S2052252520015675