3. (4 points) You have recently isolated a protein and are currently determining the structure of the protein. Gel filtration chromatography indicated a molecular weight of approximately 320 kDa. Treatment with a low concentration of guanidinium hydrochloride (not enough to fully denature the protein) followed by gel filtration chromatography gave a protein of 160 kDa. SDS-PAGE of the protein gave 3 bands with weights of 30 kDa, 50 kDa, and 80 kDa. Further treatment with B-mercaptoethanol followed by SDS-PAGE gave 3 bands with weights of 30 kDa, 40 kDa, and 50 kDa. From this information, describe the makeup of this protein in terms of number of subunits and how those subunits are held together. Your explanation should include how the different treatments provide the information.