Direct AFM observations of impurity effects on a lysozyme crystal

• Published in: Journal of crystal growth Vol. 196; no. 2; pp. 503 - 510
• Main Authors: Nakada, Toshitaka, Sazaki, Gen, Miyashita, Satoru, Durbin, Stephen D, Komatsu, Hiroshi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-01-1999; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Atomic force microscopy; Biological and medical sciences; Dimer; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; High pressure liquid chromatography; Impurity; Lysozyme; Proteins; 61.16.Ch; Atomic force microscopy; Impurity; 61.72.−y; High pressure liquid chromatography; 61.25.Ag; Dimer; Lysozyme; 81.10.Dn; Crystal growth; Enzyme; Glycosidases; Crystallization; Hydrolases; O-Glycosidases; Protein
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(98)00875-6

Impurity effects on the growth of tetragonal lysozyme crystals have been studied using in situ atomic force microscopy. Commercially available hen egg white lysozyme was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis with silver staining, and purified by re-crystallization and successive high pressure liquid chromatography. On the (1
1
0) crystal surface, there was no significant difference in morphology between crystals grown in commercial and in purified solutions. On the (1
0
1) surface, however, a large number of small particles were found when the crystal was grown in the commercial solution, while the surface grown in the purified solution was quite smooth. Among the typical residual impurities contained in commercial lysozyme, only covalently bound lysozyme dimer yielded such particles. From measurements of particle separation and an estimate of the critical nucleation size, we infer that the particles reduced the step velocity according to the mechanism described by Cabrera et al. [N. Cabrera, D.A. Vermilyea, in: R.H. Doremus et al. (Eds.), Growth and Perfection of Crystals, 1958, P. 393].