Glycosylation patterns with MALS
Posted: Wed Feb 27, 2019 9:54 am
Can glycosylation patterns or unstructured parts of proteins be identified or differentiated using MALS?
Yes, this is one of the most powerful aspects of MALS analysis. If you do standard gel filtration analysis and the protein appears to be a dimer by retention time but MALS tells you it is actually a monomer, this is a good sign of a partially unfolded protein.
In some instances, measurements of diffusion coefficient and hydrodynamic radius by online DLS can help nail down size as well, which can be compared to molar mass to assess overall structure. Glycosylation patterns per se cannot really be assessed by these techniques, since they do not have the resolution to determine where glycosylation occurs on the protein. However, SEC-MALS can determine overall degree of glycosylation using the Protein Conjugate analysis method), which combines UV, RI and MALS signals to calculate the protein molar mass and glycan molar mass in the conjugate at each elution volume.
[answer provided by Kushol Gupta, Ph.D., University of Pennsylvania]