Synechocystis sp. PCC6803 possesses a two-component polyhydroxyalkanoic acid synthase similar to that of anoxygenic purple sulfur bacteria |
| |
Authors: | Silke Hein H Tran A Steinbüchel |
| |
Institution: | Institut für Mikrobiologie, Westf?lische Wilhelms-Universit?t Münster, Corrensstra?e 3, D-48149 Münster, Germany Tel.: +49-251-83-39821; Fax: +49-251-83-38388 e-mail: steinbu@uni-muenster.de, DE
|
| |
Abstract: | During cultivation under storage conditions with BG11 medium containing acetate as a carbon source, Synechocystis sp. PCC6803 accumulated poly(3-hydroxybutyrate) up to 10% (w/w) of the cell dry weight. Our analysis of the complete Synechocystis sp. PCC6803 genome sequence, which had recently become available, revealed that not only the open reading frame slr1830 (which
was designated as phaC) but also the open reading frame slr1829, which is located colinear and upstream of phaC, most probably represent a polyhydroxyalkanoic acid (PHA) synthase gene. The open reading frame slr1829 was therefore designated
as phaE. The phaE and phaC gene products exhibited striking sequence similarities to the corresponding PHA synthase subunits PhaE and PhaC of Thiocystis violacea, Chromatium vinosum, and Thiocapsa pfennigii. The Synechocystis sp. PCC6803 genes were cloned using PCR and were heterologously expressed in Escherichia coli and in Alcaligenes eutrophus. Only coexpression of phaE and phaC partially restored the ability to accumulate poly(3-hydroxybutyrate) in the PHA-negative mutant A. eutrophus PHB–4. These results confirmed our hypothesis that coexpression of the two genes is necessary for the synthesis of a functionally
active Synechocystis sp. PCC6803 PHA synthase. PHA granules were detected by electron microscopy in these cells, and the PHA-granule-associated
proteins were studied. Western blot analysis of Synechocystis sp. PCC6803 crude cellular extracts and of granule-associated proteins employing antibodies raised against the PHA synthases
of A. eutrophus (PhaC) and of C. vinosum (PhaE and PhaC) revealed no immunoreaction.
Received: 11 March 1998 / Accepted: 2 June 1998 |
| |
Keywords: | Synechocystis sp PCC6803 Biodegradable polyester Polyhydroxyalkanoic acid Poly(3-hydroxybutyric acid) PHA-synthase PhaE PhaC |
本文献已被 SpringerLink 等数据库收录! |
|