Subunit structure of aldolase

A new crystal form of rabbit muscle aldolase shows that the molecule has 222 symmetry to at least 4-angstrom resolution, and hence that the gross conformation of the four subunits is the same. Comparison of the new form with a previously reported form establishes the number of molecules per unit cell, n, in the older form. For an independent check, the "crystal-volume and protein-content method" was developed to determine n without directly measuring the water content of the crystals.