An aqueous solution of volume $300 \mathrm{~cm}^{3}$ contains $0.63 \mathrm{~g}$ of protein. The osmotic pressure of the solution at $300 \mathrm{~K}$ is 1.29 mbar. The molar mass of the protein is ___________ $\mathrm{g} ~\mathrm{mol}^{-1}$

Given : R = 0.083 L bar K$^{-1}$ mol$^{-1}$