Yeast NAD(+)-specific isocitrate dehydrogenase (IDH) is an allosterically regulated octameric enzyme composed of two types of homologous subunits designated IDH1 and IDH2. Based on sequence comparisons and structural models, both subunits are predicted to have adenine nucleotide binding sites. This was tested by alanine replacement of residues in putative sites in each subunit. Targets included adjacent aspartate/isoleucine residues implicated as important for determining cofactor specificity in related dehydrogenases and a residue in each IDH subunit in a position occupied by histidine in other cofactor binding sites. The primary kinetic effects of D286A/I287A and of H281A replacements in IDH2 were found to be a dramatic reduction in apparent affinity of the holoenzyme for NAD(+) and a concomitant reduction in V(max). Ligand binding assays also showed that the H281A mutant enzyme fails to bind NAD(+) under conditions that are saturating for the wild-type enzyme. In contrast, the primary effect of corresponding D279A/D280A and of R274A replacements in IDH1 is a reduction in holoenzyme binding of AMP, with concomitant alterations in kinetic and isocitrate binding properties normally associated with activation by this allosteric effector. These results suggest that the nucleotide cofactor binding site is primarily contributed by the IDH2 subunit, whereas the homologous nucleotide binding site in IDH1 has evolved for regulatory binding of AMP. These results are consistent with previous studies demonstrating that the catalytic isocitrate binding sites are comprised of residues primarily contributed by IDH2, whereas sites for regulatory binding of isocitrate are contributed by analogous residues of IDH1. In this study, we also demonstrate that a prerequisite for holoenzyme binding of NAD(+) is binding of isocitrate/Mg(2+) at the IDH2 catalytic site. This is comparable to the dependence of AMP binding upon binding of isocitrate at the IDH1 regulatory site.
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
Evidence ID | Analyze ID | Gene/Complex | Systematic Name/Complex Accession | Qualifier | Gene Ontology Term ID | Gene Ontology Term | Aspect | Annotation Extension | Evidence | Method | Source | Assigned On | Reference |
---|
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.
Evidence ID | Analyze ID | Gene | Gene Systematic Name | Phenotype | Experiment Type | Experiment Type Category | Mutant Information | Strain Background | Chemical | Details | Reference |
---|
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
Evidence ID | Analyze ID | Gene | Gene Systematic Name | Disease Ontology Term | Disease Ontology Term ID | Qualifier | Evidence | Method | Source | Assigned On | Reference |
---|
Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.
Evidence ID | Analyze ID | Regulator | Regulator Systematic Name | Target | Target Systematic Name | Direction | Regulation of | Happens During | Regulator Type | Direction | Regulation Of | Happens During | Method | Evidence | Strain Background | Reference |
---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through its pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
Site | Modification | Modifier | Source | Reference |
---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.
Evidence ID | Analyze ID | Interactor | Interactor Systematic Name | Interactor | Interactor Systematic Name | Allele | Assay | Annotation | Action | Phenotype | SGA score | P-value | Source | Reference | Note |
---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.
Evidence ID | Analyze ID | Interactor | Interactor Systematic Name | Interactor | Interactor Systematic Name | Assay | Annotation | Action | Modification | Source | Reference | Note |
---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through its pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
Complement ID | Locus ID | Gene | Species | Gene ID | Strain background | Direction | Details | Source | Reference |
---|
Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; download this table as a .txt file using the Download button;
Evidence ID | Analyze ID | Dataset | Description | Keywords | Number of Conditions | Reference |
---|