Photo-isomerization of the isolated photoactive yellow protein chromophore: What comes before the primary step?

Author(s):  
Cate S Anstöter ◽  
Basile Curchod ◽  
Jan RR Verlet

Photoactive proteins typically rely on structural changes in a small chromophore to initiate a biological response. While these changes often involve isomerization as the “primary step”, preceding this is an...

2012 ◽  
Vol 116 (44) ◽  
pp. 13172-13182 ◽  
Author(s):  
Marijke Hospes ◽  
Johannes H. Ippel ◽  
Rolf Boelens ◽  
Klaas J. Hellingwerf ◽  
Johnny Hendriks

2003 ◽  
Vol 17 (2-3) ◽  
pp. 345-353 ◽  
Author(s):  
Eriko Mano ◽  
Hironari Kamikubo ◽  
Yasushi Imamoto ◽  
Mikio Kataoka

Photoactive yellow protein (PYP) is a photoreceptor protein for the negative phototaxis ofEctothiorhodospira halophila. The crystal structures of several photo‒intermediates have been revealed by X-ray crystallography. In the crystal structure of the active intermediate, PYPM, no significant structural changes were observed except for the vicinity of the chromophore. On the contrary, spectroscopic studies with solution condition demonstrated that global structural changes occur during the photo‒cycle. In order to reveal the origin of the discrepancies, we measured the reaction kinetics upon illumination under crystal condition and to compare them with those observed under solution condition. The reactive portion decreases with the increase of crystallinity. The rate constant of PYPMdecay also decreases with the increase of crystallinity. These results suggest two possibilities: (1) PYP in crystal does not react by the illumination; (2) the photoreaction rate is highly accelerated in crystal. Consequently, the photoreaction in crystal is considered to be highly influenced by the force constraint from crystalline lattice.


Structure ◽  
2004 ◽  
Vol 12 (6) ◽  
pp. 1039-1045 ◽  
Author(s):  
Spencer Anderson ◽  
Vukica Srajer ◽  
Reinhard Pahl ◽  
Sudarshan Rajagopal ◽  
Friedrich Schotte ◽  
...  

2021 ◽  
Author(s):  
Subaagari Seevaratnam

There exists a multitude of extreme thermally induced therapies for treating both benign and malignant tumors. Advancement in optics has shown prospect in clinical applications, especially monitoring oncological clinical treatments like thermal ablation. Optical coherence tomography (OCT) backscattered spectrum has demonstrated sensitivity to structural changes on the microscopic level. Envelope statistics analysis on OCT images of tissue-mimicking phantoms that are thermally modulated can provide structural information that correlates to changes in temperature. Several probability distribution functions were analyzed by looking at suitable theoretical matches to the empirical OCT data. Results indicate that the generalized gamma function was the best fit and has potential in relating the scale parameter to the size of the scatterers in the phantom. Moreover, the parameters revealed sensitivity to temperature changes, which can be further studied to understand the biological response of tissue that are exposed to extreme thermal conditions in order to improve patient care.


2021 ◽  
Author(s):  
Subaagari Seevaratnam

There exists a multitude of extreme thermally induced therapies for treating both benign and malignant tumors. Advancement in optics has shown prospect in clinical applications, especially monitoring oncological clinical treatments like thermal ablation. Optical coherence tomography (OCT) backscattered spectrum has demonstrated sensitivity to structural changes on the microscopic level. Envelope statistics analysis on OCT images of tissue-mimicking phantoms that are thermally modulated can provide structural information that correlates to changes in temperature. Several probability distribution functions were analyzed by looking at suitable theoretical matches to the empirical OCT data. Results indicate that the generalized gamma function was the best fit and has potential in relating the scale parameter to the size of the scatterers in the phantom. Moreover, the parameters revealed sensitivity to temperature changes, which can be further studied to understand the biological response of tissue that are exposed to extreme thermal conditions in order to improve patient care.


Biochemistry ◽  
2003 ◽  
Vol 42 (7) ◽  
pp. 2062-2071 ◽  
Author(s):  
Eefei Chen ◽  
Thomas Gensch ◽  
Andrew B. Gross ◽  
Johnny Hendriks ◽  
Klaas J. Hellingwerf ◽  
...  

2004 ◽  
Vol 44 (supplement) ◽  
pp. S99
Author(s):  
M. Unno ◽  
Samir F. El-Mashotoly ◽  
M. Kumauchi ◽  
N. Hamada ◽  
F. Tokunaga ◽  
...  

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