| We find that the tetramer and the dimer become less stable than the monomer as the pH is lowered. |
| The notable decrease in free energy from trimer to tetramer suggested that the aggregation process was cooperative. |
| Then we examined whether or not the quaternary structure of arrestin tetramer in solution is identical to that in crystal. |
| The tetramer is the functional unit of hemoglobin and its constituent chains are in communication with one another. |
| Numerous studies suggest that the smallest multimer with full catalytic activity is a tetramer or an octamer. |
| The aldolase cross-bridges are represented by ovals with the shaded oval indicating the cross-bridging tetramer and the unshaded oval indicating the decorating tetramer. |
