Similarity of Coomassie Dye Spectral Absorbance Dynamic of Sequentially Distant Polymeric N‐Terminal Segments of Glycine and GABA Transporters

Abstract Classical interaction of Coomassie dye with proteins stabilizes its blue dye form, resulting in 595 nm absorbance peak used in protein quantitation. We previously showed that a dynamic Coomassie interaction mode might exist in certain disordered proteins, resulting in time dependent spectral absorbance shifts, blocked by the presence of protein secondary structure. To separate unstructured GlyT1a N‐terminal peptide from transporter ordered regions and regain its sufficient affinity to Coomassie dye, we previously prepared polymeric forms of GlyT1aN peptide using special stepwise cloning technique. In this work we applied identical technique to create polymeric regions derived from the N‐termini of neurotransmitter transporters rGlyT1b, rGAT3 and rGAT1. Polymeric proteins with low secondary structure content showed very similar dynamic spectral absorbance signatures, when complexed with Coomassie dye. Diversity of their primary amino acid sequences indicates that previously not recognized microstructural similarity between them might be potentially investigated by their interaction with Coomassie Brilliant Blue G‐250.