Recording of blue light-induced energy and volume changes within the wild-type and mutated Phot-LOV1 domain from Chlamydomonas reinhardtii

Losi, Aba and Kottke, Tilman and Hegemann, Peter (2004) Recording of blue light-induced energy and volume changes within the wild-type and mutated Phot-LOV1 domain from Chlamydomonas reinhardtii. BIOPHYSICAL JOURNAL, 86 (2). pp. 1051-1060. ISSN 0006-3495, 1542-0086

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Abstract

The time-resolved thermodynamics of the flavin mononucleotide (FMN)-binding LOV1 domain of Chlamydomonas reinhardtii phot (phototropin homolog) was studied by means of laser-induced optoacoustic spectroscopy. In the wild-type protein the early red-shifted intermediate LOV715 exhibits a small volume contraction, DeltaV(715)=-1.50 ml/mol, with respect to the parent state. LOV715 decays within few mus into the covalent FMN-Cys-57 adduct LOV390, that shows a larger contraction, DeltaV(390)=-8.8 ml/mol, suggesting a loss of entropy and conformational flexibility. The high energy content of LOV390, E-390=180 kJ/mol, ensures the driving force for the completion of the photocycle and points to a strained photoreceptor conformation. In the LOV-C57S mutated protein the photoadduct is not formed and DeltaV(390) is undetected. Large effects on the measured DeltaVs are observed in the photochemically competent R58K and R58K/D31Q mutated proteins, with DeltaV(390)=-2.0 and -1.9 ml/mol, respectively, and DeltaV(715)approximate to0. The D31Q and D31N substitutions exhibit smaller but well-detectable effects. These results show that the photo-induced volume changes involve the protein region comprising Arg-58, which tightly interacts with the FMN phosphate group.

Item Type: Article
Uncontrolled Keywords: TIME-RESOLVED THERMODYNAMICS; PHOTOACTIVE YELLOW PROTEIN; PLANT PHOTORECEPTOR DOMAIN; SENSORY RHODOPSIN II; FLAVIN MONONUCLEOTIDE; LOV2 DOMAIN; STRUCTURAL-CHANGES; NATRONOBACTERIUM-PHARAONIS; CHLOROPLAST RELOCATION; ARABIDOPSIS NPH1;
Subjects: 500 Science > 530 Physics
500 Science > 570 Life sciences
Divisions: Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie
Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie
Depositing User: Dr. Gernot Deinzer
Date Deposited: 22 Jul 2021 11:19
Last Modified: 22 Jul 2021 11:19
URI: https://pred.uni-regensburg.de/id/eprint/38023

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