| Autor: |
Kallio P; Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland., Liu Z, Mäntsälä P, Niemi J, Metsä-Ketelä M |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of molecular biology [J Mol Biol] 2008 Feb 01; Vol. 375 (5), pp. 1212-21. Date of Electronic Publication: 2007 Nov 22. |
| DOI: |
10.1016/j.jmb.2007.11.044 |
| Abstrakt: |
The gene pgaM is involved in the biosynthesis of an angucycline-type polyketide antibiotic in Streptomyces sp. PGA64. It encodes a two-domain polypeptide consisting of an N-terminal flavoprotein oxygenase and a C-terminal short-chain alcohol dehydrogenase/reductase, which are fused together at the translational level as a result of end codon deletion. Here we show that translation also initiates at an internal start codon that enables independent expression of a separate reductase subunit, PgaMred. This confirms that the gene exhibits a rare viral-like arrangement of two overlapping reading frames that allows simultaneous expression of two alternative forms of the protein. Together, these two proteins associate to form a stable non-covalent complex, the native form of PgaM. The reductase subunit PgaMred is shown to provide enzyme stability and to affect the redox state of the oxygenase domain FAD. Finally, a model for the quaternary structure of the complex that explains the necessity for a nested gene system and the unusual behaviour of the protein subunits in vitro is presented. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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