RKI1/YOR095C Summary 
RKI1 BASIC INFORMATION
| Standard Name | RKI1 |
|---|---|
| Systematic Name | YOR095C |
| Feature Type | ORF, Verified |
| Description | Ribose-5-phosphate ketol-isomerase, catalyzes the interconversion of ribose 5-phosphate and ribulose 5-phosphate in the pentose phosphate pathway; participates in pyridoxine biosynthesis (1, 2 and see Summary Paragraph) 
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| Name Description | Ribose-5-phosphate Ketol-Isomerase 1 |
| GO Annotations | All RKI1 GO evidence and references |
|---|---|
| View Computational GO annotations for RKI1 | |
| Molecular Function | |
| Manually curated | |
| Biological Process | |
| Manually curated | |
| Cellular Component | |
| High-throughput |
| Pathways |
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| Mutant Phenotype | All RKI1 Phenotype details and references |
|---|---|
| Classical genetics | |
| null | |
| Large-scale survey | |
| null |
| Interactions | RKI1 All interactions details and references |
|---|---|
| 11 total interaction(s) for 8 unique genes/features. | |
| Physical Interactions |
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| Genetic Interactions |
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| External Links | All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB |
|---|
| Primary SGDID | S000005621 |
|---|
RKI1 RESOURCES
| SGD ORF map | GBrowse |
|---|---|
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Click on histogram for expression summary
Expression Summary
ADDITIONAL INFORMATION for RKI1
SUMMARY PARAGRAPH for RKI1
Rki1p is a D-ribose-5-phosphate ketol-isomerase (EC:5.3.1.6) in the non-oxidative branch of the pentose phosphate pathway (1). In addition to the pentose phosphate pathway, Rki1p is also involved in pyridoxine biosynthesis. Pyridoxine is the major form of vitamin B6 and is a precursor for pyridoxal phosphate, an important coenzyme for amino acid metabolism (2). RKI1 is transcriptionally repressed in response to lithium chloride, and may be transcriptionally regulated in response to stress, as suggested by promoter analysis (3, 1). Active Rki1p is a tetramer and Rki1p is very unstable in crude extracts (2, 1). Rki1p localizes to the nucleus and cytoplasm (4).
rki1 null mutants are inviable, which suggests that Rki1p has an additional essential role other than its role in the non-oxidative part of the pentose-phosphate pathway since defects in genes encoding other enzymes of this part of the pentose phosphate pathway (rpe1 null mutants) are not lethal (2, 1). rki1-[R189K] mutants display a pyridoxine auxotrophy, and Rki1p-[R189K] mutant proteins contain 0.6% of the activity of Rki1p, appear to have an altered 3-dimensional structure, and form dimers instead of tetramers (2).
Rki1p has similarity to the ribose 5-phosphate ketol-isomerases from many prokaryotes and eukaryotes that include: Schizosaccharomyces pombe, Arabidopsis thaliana, Caenorhabditis elegans (B0280.3), Drosophila melanogaster, mouse (RPI) and humans. Mutations in the human homolog RPIA (OMIM) are associated with ribose 5-phosphate isomerase deficiency (OMIM; 2, 5, 1).
Last updated: 2005-12-14
REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for RKI1]
| 1) | Miosga T and Zimmermann FK (1996) Cloning and characterization of the first two genes of the non-oxidative part of the Saccharomyces cerevisiae pentose-phosphate pathway. Curr Genet 30(5):404-9 |
| 2) | Kondo H, et al. (2004) Pyridoxine biosynthesis in yeast: participation of ribose 5-phosphate ketol-isomerase. Biochem J 379(Pt 1):65-70 |
| 3) | Bro C, et al. (2003) Transcriptional, proteomic, and metabolic responses to lithium in galactose-grown yeast cells. J Biol Chem 278(34):32141-9 |
| 4) | Huh WK, et al. (2003) Global analysis of protein localization in budding yeast. Nature 425(6959):686-91 |
| 5) | Graille M, et al. (2005) Crystal structure of the S. cerevisiae D-ribose-5-phosphate isomerase: comparison with the archaeal and bacterial enzymes. Biochimie 87(8):763-9 |
