Characterization of recombinant phytochrome from the cyanobacterium Synechocystis

• DOI: 10.1073/pnas.94.22.11792
• Publication Date: 2002-07-26T14:31:44Z
• Authors: Tilman Lamparter; Franz Mittmann; Wolfgang Gärtner; Thomas Börner; Elmar Hartmann; Jon Hughes
• Keywords: Phytochrome; Phycocyanobilin; Synechocystis; Tetrapyrrole

The complete sequence of the Synechocystis chromosome has revealed a phytochrome-like that yielded an authentic phytochrome when overexpressed in Escherichia coli . In this paper we describe recombinant more detail. Islands strong similarity to plant phytochromes were found throughout cyanobacterial whereas C-terminal homologies identify it as likely sensory histidine kinase, family which are related. An ≈ 300 residue portion is important for function missing from sequence, immediately front putative kinase region. apoprotein soluble and can easily be purified homogeneity by affinity chromatography. Phycocyanobilin similar tetrapyrroles covalently attached within seconds, autocatalytic process followed slow conformational changes culminating red-absorbing formation. Spectral absorbance characteristics remarkably those phytochromes, although conformation chromophore helical phytochrome. According size-exclusion chromatography native apoproteins holoproteins elute predominantly 115- 170-kDa species, respectively. Both tend form dimers vitro aggregate under low salt conditions. Nevertheless, purity solubility gene product make most attractive model molecular studies phytochrome, including x-ray crystallography.