Lysozyme

Taiji Imoto, Sojo University, Kumamoto, Japan

Published online: September 2009

DOI: 10.1002/9780470015902.a0000869.pub2

Lysozymes are lytic enzymes that hydrolyse glycosidic bonds and are widely distributed in nature. Hen egg-white lysozyme is the best characterized of all proteins and, as well as serving as a model protein for study, its antibacterial and immune function properties are exploited in medicines and food additives. Basic concepts of enzyme reaction, structure and function of protein, protein chemistry and stability of protein are described. Evolution and diversity in structure and function of lysozyme are also stated.

Key concepts

  • Fundamental concept on an enzyme reaction is elucidated in an atomic level.
  • Lysozyme is a model protein for studying on structure and function of protein.
  • The diversities in structure and function make lysozymes interesting.

Keywords: lysis; enzyme; medicine; food additive; 3D structure

Figure 1. A substrate for lysozyme. Copolymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) that is the constituent of bacterial cell walls. These sugar residues bind at sites C, D, E and F in Figure 2. The arrow shows the bond susceptible to lysozyme.
Figure 2. Three-dimensional structure of hen lysozyme. Residues Glu35 and Asp52 are shown as the catalytic groups. Residues Trp62 and Trp63 are also shown. The letters A–F in the active-site cleft schematically show the binding sites of each sugar residue of substrate, hexamer of N-acetylglucosamine. The programme MOLSCRIPT was used.
Figure 3. The reaction mechanism of lysozyme. D sugar is distorted from chair form to half-chair form on binding. Glu35 donates a proton to susceptible oxygen atom. Negative charge of Asp52 assists the formation of the carbonium ion.
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 References
    Bachali S, Jager M, Hassanin A et al. (2002) Phylogenetic analysis of invertebrate lysozymes and the evolution of lysozyme function. Journal of Molecular Evolution 54: 652–664.
    Blake CCF, Koenigh DF, Mair GA et al. (1965) Structure of hen egg white lysozyme. A three dimensional Fourier synthesis at 2 Å resolution. Nature 206: 757–761.
    Cancado FC, Valerio AA, Marana SR et al. (2007) The crystal structure of a lysozyme c from housefly Musca domestica, the first structure of a digestive lysozyme. Journal of Structural Biology 160: 83–92.
    Goto T, Abe Y, Kakuta Y et al. (2007) Crystal structure of Tapes japonica lysozyme with substrate analogue: structural basis of the catalytic mechanism and manifestation of its chitinase activity accompanied by quaternary structural change. Journal of Biological Chemistry 282: 27459–27467.
    Grutter MG, Weaver LH and Matthews BW (1983) Goose lysozyme structure: an evolutionary link between hen and bacteriophage lysozymes? Nature 303: 828–831.
    Imoto T (1997) Stabilization of protein. Cellular and Molecular Life Sciences 53: 215–223.
    Klein-Seetharaman J, Oikawa M, Grimshaw SB et al. (2002) Long-range interactions within a nonnative protein. Science 295: 1719–1722.
    Matthews BW (1996) Structural and genetic analysis of the folding and function of T4 lysozyme. FASEB Journal 36: 35–41.
    Mine S, Tate S, Ueda T, Kainosho M and Imoto T (1999) Analysis of the relationship between enzyme activity and its internal motion using nuclear magnetic resonance: 15N relaxation studies of wild-type and mutant lysozyme. Journal of Molecular Biology 286: 1547–1565.
    Phillips DC (1966) The three-dimensional structure of an enzyme molecule. Scientific American 215: 78–90.
    Vocadlo DJ, Davies GJ, Laine R and Withers SG (2001) Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate. Nature 412: 835–838.
 Further Reading
    book Imoto T, Johnson LN, North ATC, Phillips DC and Rupley JA (1972) "Vertebrate lysozymes". In: Boyer PD, Lardy H and Myrback K (eds) The Enzymes, 2nd edn, vol. 7 pp. 665–868. New York: Academic Press.
    book Jolles P (ed.) (1996) Lysozymes: Model enzymes in biochemistry and biology. Basel: Birkhauser Verlag.

Related Sub-Topics:

Protein Structure | Enzymes: Structure and Action Mechanism
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Article Title: Lysozyme
 
How to Cite close
Imoto, Taiji(Sep 2009) Lysozyme. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000869.pub2]