Abstract
Tyrosine-159 of the Streptomyces R61 penicillin-sensitive DD-peptidase was replaced by serine or phenylalanine. The second mutation yielded a very poorly active protein whose rate of penicillin binding was also drastically decreased, except for the reactions with nitrocefin and methicillin. The consequences of the first mutation were more surprising, since a large proportion of the thiolesterase activity was retained, together with the penicillin-binding capacity. Conversely, the peptidase properties was severely affected. In both cases, a drastic decrease in the transferase activity was observed. The results are compared with those obtained by mutation of the corresponding residue in the class A beta-lactamase of Streptomyces albus G.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Anti-Bacterial Agents / metabolism
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Base Sequence
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Chemical Phenomena
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Chemistry, Physical
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Enzyme Stability
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Escherichia coli
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Hydrogen-Ion Concentration
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Kinetics
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Lactams
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Molecular Sequence Data
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Muramoylpentapeptide Carboxypeptidase / chemistry*
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Muramoylpentapeptide Carboxypeptidase / genetics
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Muramoylpentapeptide Carboxypeptidase / metabolism*
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Mutagenesis
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Phenylalanine
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Plasmids
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Serine
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Streptomyces / enzymology*
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Structure-Activity Relationship
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Tyrosine / chemistry*
Substances
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Anti-Bacterial Agents
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Lactams
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Recombinant Proteins
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Tyrosine
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Serine
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Phenylalanine
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Muramoylpentapeptide Carboxypeptidase