The initial stage of crystallization of lysozyme: a differential scanning calorimetric (DSC) study

• Published in: Journal of crystal growth 1999-07, Vol.204 (1), p.191-200
• Main Authors: Igarashi, Koichi, Azuma, Masayuki, Kato, Jyoji, Ooshima, Hiroshi
• Format: Article
• Language: English
• Subjects: Aggregation; Attractive interaction; Biological and medical sciences; Cross-disciplinary physics: materials science; rheology; Differential scanning calorimetry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Growth from solutions; Heat capacity; In solution. Condensed state. Thin layers; Initial stage; Materials science; Methods of crystal growth; physics of crystal growth; Molecular biophysics; Nucleation; Physico-chemical properties of biomolecules; Physics; Protein
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(99)00181-5

The initial stage of crystallization of hen-egg-white lysozyme was investigated. Lysozyme molecules formed a structure just after the supersaturated solution was prepared. The structure could be understood as changes in solution three-dimensional structure induced by attractive interactions or aggregates with an average size of 6.5 nm. The structure formation, however, did not immediately link to crystal growth. An induction period was needed before the start of crystal growth. DSC analysis of the supersaturated solution revealed that the structure thus formed at the beginning of crystallization is transformed just before the end of the induction period. DSC analysis also revealed that the driving force of the transformation is the formation of hydrophobic bonds between lysozyme molecules. Our understanding of the behavior of lysozyme molecules before crystal growth was furthered by measurement of the ζ-potential of the aggregates. Based on the present results, a possible model of the early stage of crystal growth of lysozyme was proposed.