Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
Active-Site pKa Determination for Photoactive Yellow Protein Rationalizes Slow Ground-State Recovery. / Oktaviani, Nur Alia; Pool, Trijntje J; Yoshimura, Yuichi; Kamikubo, Hironari; Scheek, Ruud M; Kataoka, Mikio; Mulder, Frans A.A.
In: Biophysical Journal, Vol. 112, No. 10, 2017, p. 2109-2116.Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
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TY - JOUR
T1 - Active-Site pKa Determination for Photoactive Yellow Protein Rationalizes Slow Ground-State Recovery
AU - Oktaviani, Nur Alia
AU - Pool, Trijntje J
AU - Yoshimura, Yuichi
AU - Kamikubo, Hironari
AU - Scheek, Ruud M
AU - Kataoka, Mikio
AU - Mulder, Frans A.A.
N1 - Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.
PY - 2017
Y1 - 2017
N2 - The ability to avoid blue-light radiation is crucial for bacteria to survive. In Halorhodospira halophila, the putative receptor for this response is known as photoactive yellow protein (PYP). Its response to blue light is mediated by changes in the optical properties of the chromophore para-coumaric acid (pCA) in the protein active site. PYP displays photocycle kinetics with a strong pH dependence for ground-state recovery, which has remained enigmatic. To resolve this problem, a comprehensive pKa determination of the active-site residues of PYP is required. Herein, we show that Glu-46 stays protonated from pH 3.4 to pH 11.4 in the ground (pG) state. This conclusion is supported by the observed hydrogen-bonded protons between Glu-46 and pCA and Tyr-42 and pCA, which are persistent over the entire pH range. Our experimental results show that none of the active-site residues of PYP undergo pH-induced changes in the pG state. Ineluctably, the pH dependence of pG recovery is linked to conformational change that is dependent upon the population of the relevant protonation state of Glu-46 and the pCA chromophore in the excited state, collaterally explaining why pG recovery is slow.
AB - The ability to avoid blue-light radiation is crucial for bacteria to survive. In Halorhodospira halophila, the putative receptor for this response is known as photoactive yellow protein (PYP). Its response to blue light is mediated by changes in the optical properties of the chromophore para-coumaric acid (pCA) in the protein active site. PYP displays photocycle kinetics with a strong pH dependence for ground-state recovery, which has remained enigmatic. To resolve this problem, a comprehensive pKa determination of the active-site residues of PYP is required. Herein, we show that Glu-46 stays protonated from pH 3.4 to pH 11.4 in the ground (pG) state. This conclusion is supported by the observed hydrogen-bonded protons between Glu-46 and pCA and Tyr-42 and pCA, which are persistent over the entire pH range. Our experimental results show that none of the active-site residues of PYP undergo pH-induced changes in the pG state. Ineluctably, the pH dependence of pG recovery is linked to conformational change that is dependent upon the population of the relevant protonation state of Glu-46 and the pCA chromophore in the excited state, collaterally explaining why pG recovery is slow.
KW - Journal Article
U2 - 10.1016/j.bpj.2017.04.008
DO - 10.1016/j.bpj.2017.04.008
M3 - Journal article
VL - 112
SP - 2109
EP - 2116
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 10
ER -