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

Deforce, Lily; Tokutomi, Satoru; Song, Pill‐Soon

doi:10.1021/bi00182a021

Cited by 24 publications

(25 citation statements)

References 30 publications

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“…The variable selection method (Manavalan & Johnson, 1987) is recommended only for data that go to at least 190 nm, with 184 nm being the preferred lower wavelength limit. Deforce et al (1994) showed that secondary structure predictions made for phytochrome using the method of Yang et al (1986) correlate well with results obtained using both the method of Manavalan and Johnson (1987) and convex constraint analysis as described by Perczel et al (1992). Truncation of the spectra at 200 nm resulted in deviations from the magnitude of each component from that previously reported.…”

Section: Methodssupporting

confidence: 71%

Protein Kinase A-Catalyzed Phosphorylation and Its Effect on Conformation in Phytochrome A

1996

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Phytochromes are ubiquitous red/far-red wavelength-sensitive photoreceptors in plants. Oat phytochrome A is a phosphoprotein. Phytochrome A (phyA) possesses two spatially different sites for phosphorylation with cAMP-dependent protein kinase (PKA) [McMichael & Lagarias (1990) Biochemistry 29, 3872-3878]. To assess the modulation of protein conformation by phosphorylation/dephosphorylation and its possible implication in phytochrome-mediated signal transduction, the conformations of phytochrome have been probed by PKA catalyzed phosphorylation. The phosphorylated species were purified and analyzed, along with untreated phytochrome, by limited proteolysis, circular dichroism (CD) and fluorescence quenching measurements. No significant changes in secondary structure of the phyA molecule after its phosphorylation were observed by CD. However, a subtle topographic and/or electrostatic effect of the phytochrome phosphorylation was detected by the time-resolved fluorescence quenching of Trp residues with Cs+ ions. N-Terminal phosphorylation at Ser17 was unique to the Pr form, but both Pr and Pfr phytochromes were phosphorylated at the hinge region to some extent. Phosphorylation at the hinge region resulted in noticeable changes in the proteolytic patterns, inhibiting cleavage near the phosphorylation site and favoring tryptic digestion of the Lys536-Asn537 peptide bond. Phosphorylation at the N-terminus did not cause observable changes in the helical structure of this region, but had an inhibitory effect on proteinase V8 accessibility at a site near the chromophore attachment. The functional relevance of protein phosphorylation of phyA is also discussed.

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Section: Methodssupporting

confidence: 71%

Protein Kinase A-Catalyzed Phosphorylation and Its Effect on Conformation in Phytochrome A

1996

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“…On Pr/Pfr phototransformation, the NTE region undergoes a conformational change from random coil to amphiphilic a-helix, which then interacts with the chromophore in the Pfr form (Parker et al, 1992;Deforce et al, 1994). Also, two Trp residues near the core regulatory region of oat phyA become preferentially exposed in the Pfr form (Wells et al, 1994).…”

Section: Discussionmentioning

confidence: 99%

Phytochrome Phosphorylation Modulates Light Signaling by Influencing the Protein–Protein Interaction[W]

et al. 2004

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Plant photoreceptor phytochromes are phosphoproteins, but the question as to the functional role of phytochrome phosphorylation has remained to be elucidated. We investigated the functional role of phytochrome phosphorylation in plant light signaling using a Pfr-specific phosphorylation site mutant, Ser598Ala of oat (Avena sativa) phytochrome A (phyA). The transgenic Arabidopsis thaliana (phyA-201 background) plants with this mutant phyA showed hypersensitivity to light, suggesting that phytochrome phosphorylation at Serine-598 (Ser598) in the hinge region is involved in an inhibitory mechanism. The phosphorylation at Ser598 prevented its interaction with putative signal transducers, Nucleoside Diphosphate Kinase-2 and Phytochrome-Interacting Factor-3. These results suggest that phosphorylation in the hinge region of phytochromes serves as a signal-modulating site through the protein–protein interaction between phytochrome and its putative signal transducer proteins.

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“…Phytochromes are composed of several domains known as an N-terminal extension (amino acid residues 1-65) that undergoes conformational change upon phototransformation, an N-terminal chromophore lyase domain (1-407) for chromophore attachment, Per/Arnt/Sim (PAS)-related domains (611-870), and a histidine kinase-related domain (871-1192). [31][32][33] We initially constructed several phyA deletion mutants lacking the N or C terminus ( Figure 2A). Assembly of the full-length (1-1129), A957 (1-957), A407 (1-407), AD65 (66-1129), and AC (574-1129) constructs into holophytochromes was verified by Zn blot analysis ( Figure 2B), and the proteins showed the appropriate Pr/Pfr spectra of phyA (data not shown).…”

Section: Interaction Of Ndpk2 With Phytochromesmentioning

confidence: 99%

Structural Analysis of Arabidopsis thaliana Nucleoside Diphosphate Kinase-2 for Phytochrome-mediated Light Signaling

Kim

Shen

et al. 2004

Journal of Molecular Biology

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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

Cited by 24 publications

References 30 publications

Protein Kinase A-Catalyzed Phosphorylation and Its Effect on Conformation in Phytochrome A

Protein Kinase A-Catalyzed Phosphorylation and Its Effect on Conformation in Phytochrome A

Phytochrome Phosphorylation Modulates Light Signaling by Influencing the Protein–Protein Interaction[W]

Structural Analysis of Arabidopsis thaliana Nucleoside Diphosphate Kinase-2 for Phytochrome-mediated Light Signaling

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