The streptothricin hydrolase (SttH), which is a member of the isochorismatase-like hydrolase (ILH) super-family, catalyzes the hydrolysis of the streptolidine lactam group in streptothricin (ST) antibiotics, thereby inactivating them. In this study we identified a novel homologous gene (sttH-sn) and sequenced the flanking regions of the sttH and sttH-sn genes. The organization of genes around the sttH, sttH-sn, and ILH genes revealed that a number of the genes were clustered with genes encoding oxidoreductases with molybdopterin binding subunits, suggesting that the true role of these gene products (SttHs and a number of ILHs) might have to do with the chemical modification of molybdopterin, rather than ST-resistance. In addition, mutant enzymes were constructed in which Ser was substituted for highly conserved Cys-176 and Cys-158 of SttH and SttH-sn respectively, and no enzyme activities were detected. Thus, biochemically, these ILHs were found to be "cysteine hydrolases."
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| rdf:type | |
| rdfs:comment |
The streptothricin hydrolase (SttH), which is a member of the isochorismatase-like hydrolase (ILH) super-family, catalyzes the hydrolysis of the streptolidine lactam group in streptothricin (ST) antibiotics, thereby inactivating them. In this study we identified a novel homologous gene (sttH-sn) and sequenced the flanking regions of the sttH and sttH-sn genes. The organization of genes around the sttH, sttH-sn, and ILH genes revealed that a number of the genes were clustered with genes encoding oxidoreductases with molybdopterin binding subunits, suggesting that the true role of these gene products (SttHs and a number of ILHs) might have to do with the chemical modification of molybdopterin, rather than ST-resistance. In addition, mutant enzymes were constructed in which Ser was substituted for highly conserved Cys-176 and Cys-158 of SttH and SttH-sn respectively, and no enzyme activities were detected. Thus, biochemically, these ILHs were found to be "cysteine hydrolases."
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| skos:exactMatch | |
| uniprot:name |
Biosci. Biotechnol. Biochem.
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| uniprot:author |
Hamano Y.,
Maruyama C.
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| uniprot:date |
2009
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| uniprot:pages |
2494-2500
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| uniprot:title |
The biological function of the bacterial isochorismatase-like hydrolase SttH.
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| uniprot:volume |
73
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| dc-term:identifier |
doi:10.1271/bbb.90499
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