Modifications of stability and function of lysozyme

Taiji Imoto, Hidenori Yamada, Kiyotaka Okazaki, Tadashi Ueda, Ryota Kuroki, Takanori Yasukochi

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Approaches to improving the functionality of lysozyme are presented. Lysozyme was variously modified and the stabilities of the derivatives were determined by thermal denaturation experiments. Contributions of salt bridge(s), hydrophobic interactions(s), and cross-linkage(s) were evaluated. The stabilities against proteolysis were also considered. For the latter stability, it might be important to depress the rate of unfolding, i.e., to stabilize the native conformation. As a rule, salt bridges and hydrophobic interactions stabilize the native conformation and cross-linkages destabilize the denatured conformation. However, cross-linkages are apt to introduce strains in the native conformation and only suitable lengths of cross-linkages can stabilize the protein. The stabilization was shown to be generally effective in improving the functionality of proteins. Catalytic groups in lysozyme (Glu-35 and Asp-52) were variously modified and finally converted to the respective amides. The participation of these groups in the catalytic function was confirmed. The specificity of lysozyme was modified. Asp-101, which lies on the top of the active site cleft of lysozyme, was variously modified and the effects on the hydrolysis patterns of a hexamer of N-acetylglucosamine were analyzed. Some approaches to endowing lysozyme with altered functions are also presented. In order to give higher esterase activity to lysozyme, the complementarity of enzyme and substrate was investigated by modifying substrate and the active site cleft of lysozyme. An attempt was made to convert lysozyme into a transaminase by introducing pyridoxamine to the active site cleft of lysozyme. Finally, we have started to apply genetic engineering to this kind of investigation and would like to see how far we can go with protein engineering to improve the nature of proteins.

Original languageEnglish
Pages (from-to)95-107
Number of pages13
JournalJournal of Protein Chemistry
Volume6
Issue number2
DOIs
Publication statusPublished - Apr 1 1987

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Muramidase
Enzymes
Conformations
Catalytic Domain
Proteins
Hydrophobic and Hydrophilic Interactions
Salts
Pyridoxamine
Proteolysis
Protein Engineering
Genetic engineering
Denaturation
Genetic Engineering
Acetylglucosamine
Substrates
Esterases
Transaminases
Amides
Hydrolysis
Stabilization

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Imoto, T., Yamada, H., Okazaki, K., Ueda, T., Kuroki, R., & Yasukochi, T. (1987). Modifications of stability and function of lysozyme. Journal of Protein Chemistry, 6(2), 95-107. https://doi.org/10.1007/BF00247759

Modifications of stability and function of lysozyme. / Imoto, Taiji; Yamada, Hidenori; Okazaki, Kiyotaka; Ueda, Tadashi; Kuroki, Ryota; Yasukochi, Takanori.

In: Journal of Protein Chemistry, Vol. 6, No. 2, 01.04.1987, p. 95-107.

Research output: Contribution to journalArticle

Imoto, T, Yamada, H, Okazaki, K, Ueda, T, Kuroki, R & Yasukochi, T 1987, 'Modifications of stability and function of lysozyme', Journal of Protein Chemistry, vol. 6, no. 2, pp. 95-107. https://doi.org/10.1007/BF00247759
Imoto T, Yamada H, Okazaki K, Ueda T, Kuroki R, Yasukochi T. Modifications of stability and function of lysozyme. Journal of Protein Chemistry. 1987 Apr 1;6(2):95-107. https://doi.org/10.1007/BF00247759
Imoto, Taiji ; Yamada, Hidenori ; Okazaki, Kiyotaka ; Ueda, Tadashi ; Kuroki, Ryota ; Yasukochi, Takanori. / Modifications of stability and function of lysozyme. In: Journal of Protein Chemistry. 1987 ; Vol. 6, No. 2. pp. 95-107.
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