Phytochrome behaves as a dimer <i>in vivo</i>

Βrockmann, J.; RIEBLE, S.; Kazarinova‐Fukshansky, Nina; Seyfried, Max; Schäfer, Eberhard

doi:10.1111/1365-3040.ep11602037

Cited by 52 publications

(31 citation statements)

References 17 publications

(5 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pr:Pfr and Pfr:Pfr, after binding to an unknown receptor, X, become the effectors of the VLFR and the LFR, respectively. This model has been sustained to a large extent by Brockmann et al (5).…”

mentioning

confidence: 74%

Fluence-Response Curves and Action Spectra for the Very Low Fluence and the Low Fluence Response for the Induction of Kalanchoë Seed Germination

Petter

Wiemeersch²,

Rethy³

et al. 1988

Plant Physiol.

View full text Add to dashboard Cite

Germination of Kalanchoe blossfeldiana Poelin. seeds is absolutely light-requiring. Germination of one seed is the result of one out of three reactions, viz. the very low fluence response (VLFR), the low fluence response (LFR) and the high fluence response/high irradiance response. In order to demonstrate the involvement of phytochrome for both photoresponses, i.e. VLFR and LFR, action spectra for induction were determined. Fluence-response data are analyzed by means of probit analysis in order to calculate the seed population parameters, with special attention to t, or the fluence for half-maximal induction, and B, the slope in the probit diagram. Laser light was used between 620 and 800 nanometers to analyze the VLFR. Phytochrome is responsible for both photoresponses: the VLFR action spectrum demonstrates an exponential decrease in apparent photoconversion cross-section (Pr -_ Pft) up to about 800 nanometers. Assuming that Pr:Pfr-X and Pfr:Pfr-X are the effectors for the VLFR and the LFR, respectively, we estimate an average induction threshold of about 0.003% P,:P, for the VLFR and about 1% Pfr:Pf, for the LFR among individuals of the seed population.

show abstract

mentioning

confidence: 74%

Fluence-Response Curves and Action Spectra for the Very Low Fluence and the Low Fluence Response for the Induction of Kalanchoë Seed Germination

Petter

Wiemeersch²,

Rethy³

et al. 1988

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Based on the observations that the dark reversion of the Pfr/Pr heterodimer is faster than destruction and that only a small percentage of the Pfr molecules undergo dark reversion, Brockmann et al (46) hypothesized that dark reversion is only possible starting from the Pfr/Pr heterodimer state. After a light pulse shifts a phytochrome system to a 50% photoequilibrium, only 50% of the molecules can convert into the heterodimer state.…”

Section: Table I Expression Of Phytochrome Constructs In Yeastmentioning

confidence: 99%

In Vivo Characterization of Chimeric Phytochromes in Yeast

Eichenberg

Kunkel

Kretsch

et al. 1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

Phytochromes are plant photoreceptors that play a major role in photomorphogenesis. Two members of the phytochrome family have been characterized in some detail. Phytochrome A, which controls very low fluence and high irradiance responses, is rapidly degraded in the light, forms sequestered areas of phytochrome (SAPs), and does not exhibit dark reversion in monocotyledonous seedlings. Phytochrome B mediates red/ far-red reversible responses, is stable in the light, and does not form SAPs. We report on the behavior in yeast of the phytochrome apoproteins of rice PHYA, tobacco PHYB, and chimeric PHYAB and PHYBA and on the behavior of the respective holoprotein adducts after assembly with phycocyanobilin chromophore (PHY*). SAP-like formation in yeast was not observed for PHYB, but was detectable for PHYA, PHYAB, and PHYBA. Rice PHYA* did not undergo dark reversion in yeast. Surprisingly, all other tested phytochrome constructs did exhibit dark reversion, including chimeric phytochromes with a short N-terminal part of tobacco PHYB or parsley PHYA fused to rice PHYA. Furthermore, the proportion of phytochrome undergoing dark reversion and the rate of reversion were increased for both the N terminusswapped constructs and PHYBA*. These results are discussed with respect to structure/function analysis of phytochromes A and B.

show abstract

“…Avena PHYA is a dimer in its native conformation (Jones et al, 1985;Jones and Quail, 1986;Brockmann et al, 1986). The protein can be divided into two large structural domains.…”

Section: Expression Of Tobacco Phyb Apoprotein In Yeastmentioning

confidence: 99%

In vitroformation of a photoreversible adduct of phycocyanobilin and tobacco apophytochrome B

Kunkel

Tomizawa

Kern

et al. 1993

European Journal of Biochemistry

View full text Add to dashboard Cite

The light-stable tobacco phytochrome apoprotein (PHYB) expressed in yeast can be assembled with phycocyanobilin to give a photoreversible adduct. The spectral properties of the reconstituted PHYB-phycocyanobilin species were determined by absorbacen and difference absorbance spectroscopies. The holoprotein exhibits absorbance maxima at 408 nm and 712 nm for the far-red-lightabsorbing (Pfr) form and 356 nm and 658 nm for the red-light-absorbing (Pr) form. The ligation of the chromophores to the dimeric PHYB apoprotein resulted in a PHYB-phycocyanobilin adduct with the spectral properties of the Pr form. Kinetic analyses of the in vitro reconstitution for PHYB apoprotein under saturating concentrations of phycocyanobilin revealed a pseudo first-order rate constant of 2.8 X lO-*s-'. The similarity with the reported rate constant for the reconstitution of light-labile phytochrome (PHYA) from oat [Li, L.

show abstract

Phytochrome behaves as a dimer in vivo

Cited by 52 publications

References 17 publications

Fluence-Response Curves and Action Spectra for the Very Low Fluence and the Low Fluence Response for the Induction of Kalanchoë Seed Germination

Fluence-Response Curves and Action Spectra for the Very Low Fluence and the Low Fluence Response for the Induction of Kalanchoë Seed Germination

In Vivo Characterization of Chimeric Phytochromes in Yeast

In vitroformation of a photoreversible adduct of phycocyanobilin and tobacco apophytochrome B

Contact Info

Product

Resources

About