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Mechanism of Ionic Strength Dependence of Crystal Growth Rates in a Subtilsin Variant



David T. Gallagher, Q Pan, G L. Gilliland


An orthorhombic crystal form of subtilisin exhibits a systematic variation in growth rates of its three unique faces, resulting in pronounced morphology variations, depending on ionic strength. Several common salts cause a concentration-dependent change in the crystal habit from thin plates to isometric bars. The effect is analyzed in terms of the four crystal contacts in the 1.75 A resolution X-ray structure. Morphological growth fronts and the rate-limiting attachment step for growth of each face are considered, and it is concluded that ion screening of a carboxyl-carboxyl interaction in one crystal contact plays a key role in the salt-morphology effect.
Journal of Crystal Growth


crystal structure, ion screening, lattice packing, protein crystal growth, subtilisin


Gallagher, D. , Pan, Q. and Gilliland, G. (1998), Mechanism of Ionic Strength Dependence of Crystal Growth Rates in a Subtilsin Variant, Journal of Crystal Growth (Accessed June 23, 2024)


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Created October 1, 1998, Updated February 19, 2017