Premium
The Complexity of the P r to P fr Phototransformation Kinetics Is an Intrinsic Property of Native Phytochrome *
Author(s) -
Schmidt Peter,
Gertsch Thomas,
Remberg Anja,
Gärtner Wolfgang,
Braslavsky Silvia E.,
Schaffner Kurt
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb02541.x
Subject(s) - phytochrome , kinetics , homogeneous , nanosecond , phytochrome a , recombinant dna , chemistry , biophysics , stereochemistry , biology , biochemistry , botany , red light , thermodynamics , mutant , physics , arabidopsis thaliana , optics , laser , quantum mechanics , gene
Several possible origins of the complex phytochrome red to far‐red light‐absorbing phytochrome (P r P fr ) phototransformation kinetics in the nanosecond‐to‐second time range have been examined. Heterogeneity based on protein sequence is ruled out as an origin of the multi‐component kinetics because recombinant 124 kDa oat phytochrome A apoprotein reconstituted with phytochro‐mobilin and the native protein are very similar in this regard throughout this time range. The P r forms of native 124 kDa oat phytochrome A and of a homogeneous recombinant 65 kDa chromoprotein fragment exhibit thermochromic properties interpreted as arising in each case from the presence of two P r species in thermal equilibrium. They exhibit identical photochemical properties. The complex kinetics therefore cannot result from P r heterogeneity either. Thus, the presence of two P r forms in equilibrium (P r , 675 and P r , 655 ) and the complex multiex‐ponential P r P fr phototransformation kinetics observed in all time ranges are intrinsic properties of the homogeneous holoprotein of oat phytochrome A.