当前位置： SCI文献检索 > BIOCHEMISTRY期刊下所有文献 > Identification of the C=O stretching vibrations of FMN and peptide backbone by 13C-labeling of the LOV2 domain of Adiantum phytochrome3.

Identification of the C=O stretching vibrations of FMN and peptide backbone by 13C-labeling of the LOV2 domain of Adiantum phytochrome3.

Abstract：

:Phototropin, a blue-light photoreceptor in plants, has two FMN-binding domains named LOV1 and LOV2. We previously observed temperature-dependent FTIR spectral changes in the C=O stretching region (amide-I vibrational region of the peptide backbone) for the LOV2 domain of Adiantum phytochrome3 (phy3-LOV2), suggesting progressive structural changes in the protein moiety (Iwata, T., Nozaki, D., Tokutomi, S., Kagawa, T., Wada, M., and Kandori, H. (2003) Biochemistry 42, 8183-8191). Because FMN also possesses two C=O groups, in this article, we aimed at assigning C=O stretching vibrations of the FMN and protein by using 13C-labeling. We assigned the C(4)=O and C(2)=O stretching vibrations of FMN by using [4,10a-13C2] and [2-13C] FMNs, respectively, whereas C=O stretching vibrations of amide-I were assigned by using 13C-labeling of protein. We found that both C(4)=O and C(2)=O stretching vibrations shift to higher frequencies upon the formation of S390 at 77-295 K, suggesting that the hydrogen bonds of the C=O groups are weakened by adduct formation. Adduct formation presumably relocates the FMN chromophore apart from its hydrogen-bonding donors. Temperature-dependent amide-I bands are unequivocally assigned by separating the chromophore bands. The hydrogen bond of the peptide backbone in the loop region is weakened upon S390 formation at low temperatures, while being strengthened at room temperature. The hydrogen bond of the peptide backbone in the alpha-helix is weakened regardless of temperature. On the other hand, structural perturbation of the beta-sheet is observed only at room temperature, where the hydrogen bond is strengthened. Light-signal transduction by phy3-LOV2 must be achieved by the progressive protein structural changes initiated by the adduct formation of the FMN.

journal_name

Biochemistry

journal_title

Biochemistry

authors

Iwata T,Nozaki D,Sato Y,Sato K,Nishina Y,Shiga K,Tokutomi S,Kandori H

doi

10.1021/bi061837v

subject

Has Abstract

pub_date

2006-12-26 00:00:00

pages

15384-91

issue

eissn

0006-2960

issn

1520-4995

journal_volume

pub_type

杂志文章

在线工具

Identification of the C=O stretching vibrations of FMN and peptide backbone by 13C-labeling of the LOV2 domain of Adiantum phytochrome3.