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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1997-4-22
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pubmed:abstractText |
Isoleucine-164 is in Van der Waals contact with two ligands (lysine-191 and aspartate-193) of the activator magnesium ion at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase from Rhodospirillum rubrum. To observe the effect of mutations in the second sphere of coordination of the metal ion, isoleucine-164 was replaced by threonine, asparagine, and aspartate. All the mutant enzymes obtained exhibit a low carboxylase activity. Ile164Asp has less than 0.1% of the wild-type carboxylase activity, Ile164Thr and Ile164Asn 6 and 1%, respectively. The mutations increase the Km(RuBP) and decrease the Kcat of the mutated enzymes. The Kcat/Km(RuBP) of Ile164Thr and Ile164Asn are 40- and 900-fold lower than wild-type, respectively. The alteration of the hydrophobic contacts between isoleucine-164 and the metal ion ligands modifies the binding of the magnesium ion and the stabilization of the 2-carboxy-arabinitol 1,5-bisphosphate and decreases the specificity factor, tau.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0006-291X
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
17
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pubmed:volume |
232
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
482-6
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pubmed:dateRevised |
2000-12-18
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pubmed:meshHeading |
pubmed-meshheading:9125206-Binding Sites,
pubmed-meshheading:9125206-Enzyme Activation,
pubmed-meshheading:9125206-Isoleucine,
pubmed-meshheading:9125206-Magnesium,
pubmed-meshheading:9125206-Mutagenesis, Site-Directed,
pubmed-meshheading:9125206-Recombinant Proteins,
pubmed-meshheading:9125206-Rhodospirillum rubrum,
pubmed-meshheading:9125206-Ribulose-Bisphosphate Carboxylase,
pubmed-meshheading:9125206-Substrate Specificity
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pubmed:year |
1997
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pubmed:articleTitle |
Role of isoleucine-164 at the active site of rubisco from Rhodospirillum rubrum.
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pubmed:affiliation |
Genencor International, South San Francisco, California 94127, USA.
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pubmed:publicationType |
Journal Article
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