Control of tetrapyrrole biosynthesis by alternate quaternary forms of porphobilinogen synthase
| Autor: | Robert Fairman, Jukka Kervinen, Eileen K. Jaffe, Alexander Zdanov, Alexander Wlodawer, Andrew Wasson, Linda Stith, Sabine Breinig |
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| Rok vydání: | 2003 |
| Předmět: |
Chlorophyll
Models Molecular Stereochemistry Allosteric regulation CHO Cells Heme Random hexamer Crystallography X-Ray chemistry.chemical_compound Structural Biology Cricetinae Animals Humans Magnesium Pyrroles Histone octamer Binding site Protein Structure Quaternary Molecular Biology Edetic Acid Glutathione Transferase Binding Sites biology Dose-Response Relationship Drug Porphobilinogen synthase Porphobilinogen Synthase Hydrogen-Ion Concentration Plants Lyase Protein Structure Tertiary Kinetics chemistry Biochemistry Tetrapyrroles biology.protein Dimerization Ultracentrifugation Morpheein Allosteric Site Protein Binding |
| Zdroj: | Nature structural biology. 10(9) |
| ISSN: | 1072-8368 |
| Popis: | Porphobilinogen synthase (PBGS) catalyzes the first common step in the biosynthesis of tetrapyrroles (such as heme and chlorophyll). Although the predominant oligomeric form of this enzyme, as inferred from many crystal structures, is that of a homo-octamer, a rare human PBGS allele, F12L, reveals the presence of a hexameric form. Rearrangement of an N-terminal arm is responsible for this oligomeric switch, which results in profound changes in kinetic behavior. The structural transition between octamer and hexamer must proceed through an unparalleled equilibrium containing two different dimer structures. The allosteric magnesium, present in most PBGS, has a binding site in the octamer but not in the hexamer. The unprecedented structural rearrangement reported here relates to the allosteric regulation of PBGS and suggests that alternative PBGS oligomers may function in a magnesium-dependent regulation of tetrapyrrole biosynthesis in plants and some bacteria. |
| Databáze: | OpenAIRE |
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