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The Photoreaction of the Photoactive Yellow Protein Domain in the Light Sensor Histidine Kinase Ppr is Influenced by the C‐terminal Domains †
Author(s) -
Kamikubo Hironari,
Koyama Tomonori,
Hayashi Michihiro,
Shirai Kumiko,
Yamazaki Yoichi,
Imamoto Yasushi,
Kataoka Mikio
Publication year - 2008
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2008.00322.x
Subject(s) - chemistry , histidine , spectral line , photochemistry , enzyme , biochemistry , physics , astronomy
To study the role of the C‐terminal domains in the photocycle of a light sensor histidine kinase (Ppr) having a photoactive yellow protein (PYP) domain as the photosensor domain, we analyzed the photocycles of the PYP domain of Ppr (Ppr‐PYP) and full‐length Ppr. The gene fragment for Ppr‐PYP was expressed in Escherichia coli, and it was chemically reconstituted with p‐ coumaric acid; the full‐length gene of Ppr was coexpressed with tyrosine ammonia‐lyase and p ‐coumaric acid ligase for biosynthesis in cells. The light/dark difference spectra of Ppr‐PYP were pH sensitive. They were represented as a linear combination of two independent difference spectra analogous to the PYP L /dark and PYP M /dark difference spectra of PYP from Halorhodospira halophila , suggesting that the pH dependence of the difference spectra is explained by the equilibrium shift between the PYP L ‐ and PYP M ‐like intermediates. The light/dark difference spectrum of Ppr showed the equilibrium shift toward PYP L compared with that of Ppr‐PYP. Kinetic measurements of the photocycles of Ppr and Ppr‐PYP revealed that the C‐terminal domains accelerate the recovery of the dark state. These observations suggest an interaction between the C‐terminal domains and the PYP domain during the photocycle, by which light signals captured by the PYP domain are transferred to the C‐terminal domains.