Solution structure and activity of mouse lysozyme M.
The three-dimensional structure of mouse lysozyme M, glycoside hydrolase, with 130 amino acids has been determined by heteronuclear NMR spectroscopy. We found that mouse lysozyme M had four alpha-helices, two 3(10)helices, and a double- and a triple-stranded anti-parallel beta-sheet, and its structure was very similar to that of hen lysozyme in solution and in the crystalline state. The pH activity profile of p-nitrophenyl penta N-acetyl-beta-D-chitopentaoside hydrolysis by mouse lysozyme M was similar to that of hen lysozyme, but the hydrolytic activity of mouse lysozyme M was lower. From analyses of binding affinities of lysozymes to a substrate analogue and internal motions of lysozymes, we suggest that the lower activity of mouse lysozyme M was due to the larger dissociation constant of its enzyme-substrate complex and the restricted internal backbone motions in the molecule.
Obita
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Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Ueda
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Imoto
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D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D002686:Chitin / Q000031:analogs & derivatives* / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D009844:Oligosaccharides / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012996:Solutions; D013379:Substrate Specificity
D005960:Glucosides; D009844:Oligosaccharides; D012996:Solutions; C055288:4-nitrophenyl-N,N',N'',N''',N''''-pentaacetyl-beta-chitopentaoside; D002686:Chitin; C031610:glycolchitin; C421864:hen egg lysozyme; D009113:Muramidase; C472450:lysozyme M, mouse