Redox and metal-regulated oligomeric state for human porphobilinogen synthase activation
| Autor: | Noriuki Nagahara, Nori Sawada, Kaoru Mitsuoka, Masayasu Minami, Fumio Arisaka |
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| Rok vydání: | 2010 |
| Předmět: |
Conformational change
Stereochemistry Reducing agent Protein subunit Clinical Biochemistry Inorganic chemistry Random hexamer Biochemistry Redox Active center Humans Histone octamer Cysteine Disulfides Ions biology Porphobilinogen synthase Chemistry Organic Chemistry Porphobilinogen Synthase Recombinant Proteins Enzyme Activation Zinc biology.protein Biocatalysis Protein Multimerization Oxidation-Reduction |
| Zdroj: | Amino acids. 41(1) |
| ISSN: | 1438-2199 |
| Popis: | The oligomeric state of human porphobilinogen synthase (PBGS) [EC.4.2.1.24] is homooctamer, which consists of conformationally heterogenous subunits in the tertiary structure under air-saturated conditions. When PBGS is activated by reducing agent with zinc ion, a reservoir zinc ion coordinated by Cys(223) is transferred in the active center to be coordinated by Cys(122), Cys(124), and Cys(132) (Sawada et al. in J Biol Inorg Chem 10:199-207, 2005). The latter zinc ion serves as an electrophilic catalysis. In this study, we investigated a conformational change associated with the PBGS activation by reducing agent and zinc ion using analytical ultracentrifugation, negative staining electron microscopy, native PAGE, and enzyme activity staining. The results are in good agreement with our notion that the main component of PBGS is octamer with a few percent of hexamer and that the octamer changes spatial subunit arrangement upon reduction and further addition of zinc ion, accompanying decrease in f/f (0). It is concluded that redox-regulated PBGS activation via cleavage of disulfide bonds among Cys(122), Cys(124), and Cys(132) and coordination with zinc ion is closely linked to change in the oligomeric state. |
| Databáze: | OpenAIRE |
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