(3Z)- and (3E)-phytochromobilin are intermediates in the biosynthesis of the phytochrome chromophore
(3Z)- and (3E)-phytochromobilin are intermediates in the biosynthesis of the phytochrome chromophore
Using a high performance liquid chromatography (HPLC)-based assay, we have demonstrated that isolated oat etioplasts convert the linear tetrapyrrole biliverdin IX alpha to (3E)-phytochromobilin, the proposed precursor of the chromophore of the plant photoreceptor phytochrome. In addition to (3E)-phytochromobilin, the synthesis of a second phytochromobilin was detected by its ability to functionally assemble with recombinant oat apophytochrome A. The structure of this new pigment has been determined to be the 3Z isomer of phytochromobilin by absorption and 1H NMR spectroscopy. Like (3E)-phytochromobilin, assembly of HPLC-purified (3Z)-phytochromobilin with apophytochrome yielded a holoprotein that is spectrally indistinguishable from native oat phytochrome A. However, the postchromatographic conversion of (3Z)- to (3E)-phytochromobilin appears to be responsible for this result. Kinetic HPLC analyses have demonstrated that (3Z)-phytochromobilin is synthesized prior to the 3E isomer by oat etioplasts. We therefore propose that (3Z)-phytochromobilin is the immediate product of biliverdin IX alpha reduction by the enzyme phytochromobilin synthase. This implicates the presence of an isomerase that catalyzes the conversion of (3Z)- to (3E)-phytochromobilin, the immediate precursor of the phytochrome A chromophore.
11111-11118
Terry, M.J..
a8c2cd6b-8d35-4053-8d77-3841c2427c3b
McDowell, M.T.
55a01927-46b2-41c5-a419-c4c6cfc8d541
Lagarias, J.C.
adfeba99-ddf0-46f1-bde8-2baad0d11489
12 May 1995
Terry, M.J..
a8c2cd6b-8d35-4053-8d77-3841c2427c3b
McDowell, M.T.
55a01927-46b2-41c5-a419-c4c6cfc8d541
Lagarias, J.C.
adfeba99-ddf0-46f1-bde8-2baad0d11489
Terry, M.J.., McDowell, M.T. and Lagarias, J.C.
(1995)
(3Z)- and (3E)-phytochromobilin are intermediates in the biosynthesis of the phytochrome chromophore.
The Journal of Biological Chemistry, 270 (19), .
(PMID:7744741)
Abstract
Using a high performance liquid chromatography (HPLC)-based assay, we have demonstrated that isolated oat etioplasts convert the linear tetrapyrrole biliverdin IX alpha to (3E)-phytochromobilin, the proposed precursor of the chromophore of the plant photoreceptor phytochrome. In addition to (3E)-phytochromobilin, the synthesis of a second phytochromobilin was detected by its ability to functionally assemble with recombinant oat apophytochrome A. The structure of this new pigment has been determined to be the 3Z isomer of phytochromobilin by absorption and 1H NMR spectroscopy. Like (3E)-phytochromobilin, assembly of HPLC-purified (3Z)-phytochromobilin with apophytochrome yielded a holoprotein that is spectrally indistinguishable from native oat phytochrome A. However, the postchromatographic conversion of (3Z)- to (3E)-phytochromobilin appears to be responsible for this result. Kinetic HPLC analyses have demonstrated that (3Z)-phytochromobilin is synthesized prior to the 3E isomer by oat etioplasts. We therefore propose that (3Z)-phytochromobilin is the immediate product of biliverdin IX alpha reduction by the enzyme phytochromobilin synthase. This implicates the presence of an isomerase that catalyzes the conversion of (3Z)- to (3E)-phytochromobilin, the immediate precursor of the phytochrome A chromophore.
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Published date: 12 May 1995
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Local EPrints ID: 182705
URI: http://eprints.soton.ac.uk/id/eprint/182705
ISSN: 0021-9258
PURE UUID: 2251e472-56c3-4791-b746-6cb79468d140
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Date deposited: 12 May 2011 10:55
Last modified: 11 Dec 2021 03:12
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Author:
M.T. McDowell
Author:
J.C. Lagarias
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