Resonance Raman spectroscopic study of the tryptic 39‐kDa fragment of phytochrome

FEBS Letters

Hildebrandt, P¹  Kneip, C¹  Schlamann, W¹  Braslavsky, S.E¹  Schaffner, K¹ 

[1] Max-Planck-Institut für Strahlenchemie, Postfach 101365, D-45413 Mülheim, Germany

关键词: Phytochrome;    Tryptic fragment;    Tetrapyrrole;    Photoisomerization;    Resonance Raman;   

DOI  :  10.1016/S0014-5793(00)02069-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The 39-kDa fragment of oat phytochrome phyA, obtained by tryptic digestion at the amino acids 65 and 425, was studied by resonance Raman spectroscopy. The parent state P_r reveals far-reaching similarities with that of the native phytochrome implying that the structures of the tetrapyrrole chromophore and its immediate protein environment are not affected by the proteolysis. However, the resonance Raman spectrum of the final product of the P_r phototransformation, denoted as P_bl, is more closely related to that of the P_fr precursor of the native phytochrome, i.e. meta-R_C, rather than to that of P_fr itself. The resonance Raman spectra indicate a high conformational flexibility of the chromophore in P_bl so that, unlike in P_fr, the tetrapyrrole rings C and D adopt a largely coplanar conformation. The protein interactions with ring D of the chromophore, which in the native phytochrome stabilize the specific chromophore structure of P_fr, cannot be established in the 39-kDa fragment due to the lack of the major C-terminal part of the protein. These findings, furthermore, support the view that the meta-R_C→P_fr transition is associated with a coupling of chromophore and protein structural changes that represent crucial events for the photoactivation of phytochrome.

【 授权许可】

Unknown