1H nuclear magnetic resonance studies of the interaction of urea with hen lysozyme. Origins of the conformational change induced in hen lysozyme by N-acetylglucosamine oligosaccharides.
The interaction between hen lysozyme and urea has been investigated using 1H nuclear magnetic resonance spectroscopy. Chemical shift changes for resonances of a number of residues in the vicinity of the active site of the protein have been observed in the presence of urea prior to denaturation. These shifts are similar to those induced in the hen lysozyme spectrum by the specific binding of N-acetylglucosamine (GlcNAc) in site C of the active site cleft, indicating that urea and GlcNAc induce a similar conformational change in the enzyme. This implies that the conformational changes experienced by the enzyme on the binding of GlcNAc oligosaccharides are the consequence of interactions, possibly hydrogen bonding, involving the N-acetyl group of the sugar residue bound in site C, rather than the result of contacts between the protein and the pyranose rings of the oligosaccharides. This suggests that hen lysozyme employs an induced fit type mechanism to discriminate for N-acetylated saccharides as substrates.
Lumb
K J
KJ
Inorganic Chemistry Laboratory, University of Oxford, U.K.
Dobson
C M
CM
D000117:Acetylglucosamine / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry*; D009844:Oligosaccharides / Q000737:chemistry; D011487:Protein Conformation; D011489:Protein Denaturation; D014508:Urea / Q000737:chemistry*
D009844:Oligosaccharides; D014508:Urea; D009113:Muramidase; D000117:Acetylglucosamine