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Specific glycine to alanine mutation eliminates dynamic interaction of polymeric GlyT1a N‐terminus with Coomassie Brilliant Blue G‐250
Author(s) -
Baliova Martina,
Jursky Frantisek
Publication year - 2018
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201700412
Subject(s) - absorbance , coomassie brilliant blue , alanine , circular dichroism , chemistry , glycine , urea , bradford protein assay , chromophore , chromatography , biophysics , biochemistry , amino acid , staining , biology , photochemistry , genetics
Abstract We previously found that multimeric GlyT1aN16 protein exhibits increased diffusion in a polyacrylamide gel and shows an unusual time‐dependent absorbance rearrangement, as revealed by the Bradford assay. Here, we find that glycine to alanine mutation eliminates the absorbance shift, but not the altered diffusion properties of GlyT1aN16, indicating that these two phenomena are not interconnected. The absorbance shift is apparent with both native and urea‐denatured GlyT1aN16, suggesting that the effect is either not dependent on protein structure, or the required structure is restored very quickly following denaturant removal. In the far‐UV spectra, circular dichroism (CD) curves for both wild‐type and mutated GlyT1aN16 are under the zero line, indicating largely unstructured character. However, a significant shift of the mutant CD curve suggests possible microstructural heterogeneity. Deconvolution of the CD data indicates a potential 3‐fold increase in isolated helical content, which would inhibit an absorbance shift, as we demonstrated previously. These results suggest that, in addition to protein quantification, Coomassie Brilliant Blue G‐250 can be used to reveal certain properties of the secondary structure of proteins.