Phototransformation of pea phytochrome A induces an increase in alpha-helical folding of the apoprotein: comparison with a monocot phytochrome A and CD analysis by different methods.
The photoreversible conformational change associated with the Pr-->Pfr transformation of a dicot phytochrome A (Pisum sativum, pea) has been probed by circular dichroism (CD) studies. Three different CD analysis methods have been used to determine the secondary structure of pea phytochrome A in both Pr and Pfr forms. We have shown that the secondary structure of dicot pea phytochrome A is very similar to the structure of monocot oat phytochrome A which was determined earlier [Sommer & Song (1990) Biochemistry 29, 1943-1948]. As with oat phytochrome A, an increase in the alpha-helical folding of the apoprotein takes place when photochrome in the Pr form is phototransformed to the Pfr form. This conformational change might well be a general characteristic of all phytochrome A's.
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Department of Chemistry, University of Nebraska, Lincoln 68588-0304.
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Song
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D001059:Apoproteins / Q000737:chemistry* / Q000528:radiation effects; D002942:Circular Dichroism; D002523:Edible Grain / Q000737:chemistry; D007887:Fabaceae / Q000737:chemistry*; D008027:Light; D010777:Photochemistry; D010834:Phytochrome / Q000737:chemistry* / Q000528:radiation effects; D010946:Plants, Medicinal; D017433:Protein Structure, Secondary / Q000528:radiation effects*; D013053:Spectrophotometry
D001059:Apoproteins; C071907:apophytochrome; D010834:Phytochrome