3CWN
Escherichia coli transaldolase b mutant f178y
Summary for 3CWN
| Entry DOI | 10.2210/pdb3cwn/pdb |
| Related | 1ONR |
| Descriptor | Transaldolase B, SULFATE ION (3 entities in total) |
| Functional Keywords | transaldolase, aldolase, directed evolution, cytoplasm, pentose shunt, transferase |
| Biological source | Escherichia coli (strain K12) |
| Cellular location | Cytoplasm (Probable): P0A870 |
| Total number of polymer chains | 2 |
| Total formula weight | 75337.34 |
| Authors | Sandalova, T.,Schneider, G.,Samland, A. (deposition date: 2008-04-22, release date: 2008-08-05, Last modification date: 2023-08-30) |
| Primary citation | Schneider, S.,Sandalova, T.,Schneider, G.,Sprenger, G.A.,Samland, A.K. Replacement of a Phenylalanine by a Tyrosine in the Active Site Confers Fructose-6-phosphate Aldolase Activity to the Transaldolase of Escherichia coli and Human Origin. J.Biol.Chem., 283:30064-30072, 2008 Cited by PubMed Abstract: Based on a structure-assisted sequence alignment we designed 11 focused libraries at residues in the active site of transaldolase B from Escherichia coli and screened them for their ability to synthesize fructose 6-phosphate from dihydroxyacetone and glyceraldehyde 3-phosphate using a newly developed color assay. We found one positive variant exhibiting a replacement of Phe(178) to Tyr. This mutant variant is able not only to transfer a dihydroxyacetone moiety from a ketose donor, fructose 6-phosphate, onto an aldehyde acceptor, erythrose 4-phosphate (14 units/mg), but to use it as a substrate directly in an aldolase reaction (7 units/mg). With a single amino acid replacement the fructose-6-phosphate aldolase activity was increased considerably (>70-fold compared with wild-type). Structural studies of the wild-type and mutant protein suggest that this is due to a different H-bond pattern in the active site leading to a destabilization of the Schiff base intermediate. Furthermore, we show that a homologous replacement has a similar effect in the human transaldolase Taldo1 (aldolase activity, 14 units/mg). We also demonstrate that both enzymes TalB and Taldo1 are recognized by the same polyclonal antibody. PubMed: 18687684DOI: 10.1074/jbc.M803184200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.4 Å) |
Structure validation
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