Mutation of active site residues in synthetic T4-lysozyme gene and their effect on lytic activity.
The active site amino acids (Glu11 and Asp20) in T4-lysozyme have been mutated to their isosteric residues Gln or Asn and/or acidic residues such as Glu----Asp or Asp----Glu by the oligonucleotide-replacement method. Out of eight mutants so generated the mutant T4-lysozyme obtained from pTLY.Asp11 retains maximum amount of activity (approximately 16%), pTLY.Asn20 the least (0.9%) whereas pTLY.Gln11 lost completely. A systematic study of the active and inactive mutants thus generated supports the important role of Glu11 and Asp20 in T4-lysozyme activity as predicted in earlier studies.
Anand
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Division of Biological Sciences, National Research Council of Canada, Ottawa.
Stephen
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Narang
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SA
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D004252:DNA Mutational Analysis; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009113:Muramidase / Q000235:genetics* / Q000378:metabolism; D013604:T-Phages / Q000201:enzymology
D009113:Muramidase