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Structural changes during the photocycle of photoactive yellow protein monitored by ultraviolet resonance raman spectra of tyrosine and tryptophan.
J Phys Chem B. 2005 Dec 15; 109(49):23666-73.JP

Abstract

Photoactive yellow protein (PYP) is a bacterial blue light photoreceptor, and photoexcitation of dark-state PYP (PYP(dark)) triggers a photocycle that involves several intermediate states. We report the ultraviolet resonance Raman spectra of PYP with 225-250 nm excitations and investigate protein structural changes accompanying the formation of the putative signaling state denoted PYP(M). The PYP(M)-PYP(dark) difference spectra show several features of tyrosine and tryptophan, indicating environmental changes for these amino acid residues. The tyrosine difference signals show small upshifts with intensity changes in Y8a and Y9a bands. Although there are five tyrosine residues in PYP, Tyr42 and Tyr118 are suggested to be responsible for the difference signals on the basis of a global fitting analysis of the difference spectra at different excitation wavelengths and the crystal structure of PYP(dark). A further experiment on the Thr50-->Val mutant supports environmental changes in Tyr42. The observed upshift of the Y8a band suggests a weaker or broken hydrogen bond between Tyr42 and the chromophore in PYP(M). In addition, a reorientation of the OH group in Tyr42 is suggested from the upshift of the Y9a band. For tryptophan, the Raman bands of W3, W16, and W18 modes diminish in intensity upon formation of PYP(M). The loss of intensities is attributable to an exposure of tryptophan in PYP(M). PYP contains only one tryptophan (Trp119) that is located more than 10 A from the active site. Thus the observed changes are indicative of global conformational changes in protein during the transition from PYP(dark) to PYP(M). These results are in line with the currently proposed photocycle mechanism of PYP.

Authors+Show Affiliations

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16375346

Citation

El-Mashtoly, Samir F., et al. "Structural Changes During the Photocycle of Photoactive Yellow Protein Monitored By Ultraviolet Resonance Raman Spectra of Tyrosine and Tryptophan." The Journal of Physical Chemistry. B, vol. 109, no. 49, 2005, pp. 23666-73.
El-Mashtoly SF, Yamauchi S, Kumauchi M, et al. Structural changes during the photocycle of photoactive yellow protein monitored by ultraviolet resonance raman spectra of tyrosine and tryptophan. J Phys Chem B. 2005;109(49):23666-73.
El-Mashtoly, S. F., Yamauchi, S., Kumauchi, M., Hamada, N., Tokunaga, F., & Unno, M. (2005). Structural changes during the photocycle of photoactive yellow protein monitored by ultraviolet resonance raman spectra of tyrosine and tryptophan. The Journal of Physical Chemistry. B, 109(49), 23666-73.
El-Mashtoly SF, et al. Structural Changes During the Photocycle of Photoactive Yellow Protein Monitored By Ultraviolet Resonance Raman Spectra of Tyrosine and Tryptophan. J Phys Chem B. 2005 Dec 15;109(49):23666-73. PubMed PMID: 16375346.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Structural changes during the photocycle of photoactive yellow protein monitored by ultraviolet resonance raman spectra of tyrosine and tryptophan. AU - El-Mashtoly,Samir F, AU - Yamauchi,Seigo, AU - Kumauchi,Masato, AU - Hamada,Norio, AU - Tokunaga,Fumio, AU - Unno,Masashi, PY - 2005/12/27/pubmed PY - 2006/7/26/medline PY - 2005/12/27/entrez SP - 23666 EP - 73 JF - The journal of physical chemistry. B JO - J Phys Chem B VL - 109 IS - 49 N2 - Photoactive yellow protein (PYP) is a bacterial blue light photoreceptor, and photoexcitation of dark-state PYP (PYP(dark)) triggers a photocycle that involves several intermediate states. We report the ultraviolet resonance Raman spectra of PYP with 225-250 nm excitations and investigate protein structural changes accompanying the formation of the putative signaling state denoted PYP(M). The PYP(M)-PYP(dark) difference spectra show several features of tyrosine and tryptophan, indicating environmental changes for these amino acid residues. The tyrosine difference signals show small upshifts with intensity changes in Y8a and Y9a bands. Although there are five tyrosine residues in PYP, Tyr42 and Tyr118 are suggested to be responsible for the difference signals on the basis of a global fitting analysis of the difference spectra at different excitation wavelengths and the crystal structure of PYP(dark). A further experiment on the Thr50-->Val mutant supports environmental changes in Tyr42. The observed upshift of the Y8a band suggests a weaker or broken hydrogen bond between Tyr42 and the chromophore in PYP(M). In addition, a reorientation of the OH group in Tyr42 is suggested from the upshift of the Y9a band. For tryptophan, the Raman bands of W3, W16, and W18 modes diminish in intensity upon formation of PYP(M). The loss of intensities is attributable to an exposure of tryptophan in PYP(M). PYP contains only one tryptophan (Trp119) that is located more than 10 A from the active site. Thus the observed changes are indicative of global conformational changes in protein during the transition from PYP(dark) to PYP(M). These results are in line with the currently proposed photocycle mechanism of PYP. SN - 1520-6106 UR - https://www.unboundmedicine.com/medline/citation/16375346/Structural_changes_during_the_photocycle_of_photoactive_yellow_protein_monitored_by_ultraviolet_resonance_raman_spectra_of_tyrosine_and_tryptophan_ L2 - https://doi.org/10.1021/jp054772z DB - PRIME DP - Unbound Medicine ER -