Size Evolution and Composition of the Intermediate Phase During Nonclassical Protein Crystal Growth from Solution

2020-05-12T04:57:21Z (GMT) by Douglas Barlow Jan Gregus
We propose here that the intermediate nucleation phase identified in a certain case
of protein crystal growth actually consists of two distinct parts; a low density and
higher density phase. A theory for crystal growth is utilized to study the formation
and growth of each phase. Within the framework of this theory the low density phase
is shown to obey a forth order kinetic law while the high density phase is zeroth order.
The combination of these two phases is shown to be a good match for X-ray diffraction
data which is indicative of its presence. The crystal growth rate is then given
in terms of the kinetic behavior of the intermediate nucleation phase. From this, the
crystal radius is estimated and shown to compare favorably with reported size data.
A method is proposed for determining the conditions that lead to protein crystals of
largest possible size.