Small-angle x-ray studies on malate synthase from baker's yeast.

Malate synthase was investigated in solution by the small-angle X-ray scattering technique. The substrate-free enzyme was shown to have a molecular weight of 186000, a radius of gyration of 3.96 nm, a maximum particle diameter of 11.2 nm, a volume of 343 nm³, a radius of gyration of the thickness of 1.04 nm, and an axial ratio of 1:0.33. The enzyme molecule undergoes small changes in overall structure upon binding substrates. Investigation of the enzyme under prolonged exposure to X-rays led to an aggregation of the enzyme and allowed statements concerning the way of aggregation and factors influencing aggregation.