Expression and biochemical properties of a ferredoxin-dependent heme oxygenase required for phytochrome chromophore synthesis


Muramoto, Takuya, Tsurui, Noriyuki, Terry, Matthew J., Yokota, Akiho and Kohchi, Takayuki (2002) Expression and biochemical properties of a ferredoxin-dependent heme oxygenase required for phytochrome chromophore synthesis. Plant Physiology, 130, (4), 1958-1966. (doi:10.1104/pp.008128).

Download

Full text not available from this repository.

Original Publication URL: http://dx.doi.org/10.1104/pp.008128

Description/Abstract

The HY1 gene of Arabidopsis encodes a plastid heme oxygenase (AtHO1) required for the synthesis of the chromophore of the phytochrome family of plant photoreceptors. To determine the enzymatic properties of plant heme oxygenases, we have expressed the HY1 gene (without the plastid transit peptide) in Escherichia coli to produce an amino terminal fusion protein between AtHO1 and glutathione S-transferase. The fusion protein was soluble and expressed at high levels. Purified recombinant AtHO1, after glutathione S-transferase cleavage, is a hemoprotein that forms a 1:1 complex with heme. In the presence of reduced ferredoxin, AtHO1 catalyzed the formation of biliverdin IX from heme with the concomitant production of carbon monoxide. Heme oxygenase activity could also be reconstituted using photoreduced ferredoxin generated through light irradiation of isolated thylakoid membranes, suggesting that ferredoxin may be the electron donor in vivo. In addition, AtHO1 required an iron chelator and second reductant, such as ascorbate, for full activity. These results show that the basic mechanism of heme cleavage has been conserved between plants and other organisms even though the function, subcellular localization, and cofactor requirements of heme oxygenases differ substantially.

Item Type: Article
ISSNs: 0032-0889 (print)
Related URLs:
Subjects: Q Science > QK Botany
Divisions: University Structure - Pre August 2011 > School of Biological Sciences
ePrint ID: 56525
Date Deposited: 08 Aug 2008
Last Modified: 27 Mar 2014 18:39
URI: http://eprints.soton.ac.uk/id/eprint/56525

Actions (login required)

View Item View Item