MECHANISMS OF PROTEIN CRYSTAL-GROWTH - AN ATOMIC-FORCE MICROSCOPY STUDY OF CANAVALIN CRYSTALLIZATION

In situ atomic force microscopy has been used to investigate step dyna mics and surface evolution during the growth of single crystals of can avalin, a protein with a well known structure. Growth occurs by step f low on complex dislocation hillocks, and involves the formation and in corporation of small, mobile molecular clusters. Defects in the form o f hollow channels are observed and persist over growth times of severa l days. The results are used to establish a physical picture of the gr owth mechanism, and estimate the values of the free energy of the step edge, alpha, and the kinetic coefficient, beta.