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On 27th November 2021,Keisuke Kasahara (M2),Major Department of Bioengineering, received Student presentation award at the 59th annual meeting of the biophysical society of Japan.

<Student presentation award at the 59th annual meeting of the biophysical society of Japan>
This award is conferred to excellent presentations delivered by students.

<About awarded research>
Title “The mechanism by which positive supercharging mutations confer pH-independent thermal stability of an antibody.”

Supercharging is a method to improve physicochemical properties of proteins by mutating surface residues with charged amino acids. We explored how supercharging affects antibody antigen-binding fragment (Fab). Starting from a Fab antibody with the negative charge, we computationally designed a positively supercharged Fab. We found that that the positively charged Fab mutant preserved thermal stability both at pH 6 and 8, while the WT denatured at lower temperature at pH 8 than at pH 6. We further confirmed that the secondary structure and the binding affinity to the antigen were preserved. Moreover, molecular dynamics simulations revealed preferential solvation of phosphate ions to the mutant surface relative to the WT surface. We considered that more free water is released from the protein surface as the affinity of a protein to phosphate ions increases by positive supercharging, which makes the protein robust to changes in the environment. [Kasahara et al., BBRC (2021)]

<Your impression & future plan>
I do appreciate Professor Tsumoto and the lab members for all their advice and support. I would like to continue to develop my research.