Fourier transform resonance Raman spectroscopy of phytochrome

• Published in: Biochemistry (Easton) Vol. 31; no. 34; pp. 7957 - 7962
• Main Authors: Hildebrandt, Peter, Hoffmann, Andreas, Lindemann, Peter, Heibel, George, Braslavsky, Silvia E, Schaffner, Kurt, Schrader, Bernhard
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-09-1992
• Subjects: Analytical, structural and metabolic biochemistry; AVENA SATIVA; Biological and medical sciences; Chemical Phenomena; Chemistry, Physical; ESPECTROMETRIA; forms; Fourier Analysis; Fundamental and applied biological sciences. Psychology; Molecular Structure; Non metallic chromoproteins, photoproteins; Photochemistry; phytochrome; Phytochrome - chemistry; PIGMENT; PIGMENTOS; Plants - chemistry; Proteins; Raman spectroscopy; SPECTROMETRIE; Spectrum Analysis, Raman; Avena sativa; Monocotyledones; Fourier transformation; Gramineae; Photoactivation; Angiospermae; Phytochrome; Spermatophyta; Raman spectrometry; Chromoprotein; Structural analysis; Chromophore
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00149a029

The Pr and Pfr forms of phytochrome in H2O and D2O have been studied by Fourier transform resonance Raman spectroscopy with near-infrared excitation (1064 nm). It is demonstrated that this technique is a powerful method for analyzing the chromophore structures of photosensitive pigments. The high spectral quality allows discussion of vibrational assignments based on an empirical approach using previously published data obtained from model compounds. The reduction in intensity of a high-frequency band assigned to the ring-C/D methine bridge vibration is an indication for the non-coplanarity of the ring D in Pfr. The high intensity of a C-H out-of-plane vibration also supports this hypothesis. In Pr, a broad peak at approximately 1100 cm-1 is assigned to an out-of-plane vibration of a strongly hydrogen-bonded pyrrole C=NH+ group. It is missing in Pfr, suggesting deprotonation of the corresponding ring during the transformation from Pr to Pfr