The Assignment of the Different Infrared Continuum Absorbance Changes Observed in the 3000-1800-cm(-1) Region During the Bacteriorhodopsin Photocycle

Overview

Journal Biophys J

Publisher Cell Press

Specialty Biophysics

Date 2004 Aug 10

PMID 15298873

Citations 16

Authors

Florian Garczarek

Jianping Wang

Mostafa A El-Sayed

Klaus Gerwert

Affiliations

Soon will be listed here.

Abstract

The bleach continuum in the 1900-1800-cm(-1) region was reported during the photocycle of bacteriorhodopsin (bR) and was assigned to the dissociation of a polarizable proton chain during the proton release step. More recently, a broad band pass filter was used and additional infrared continua have been reported: a bleach at >2700 cm(-1), a bleach in the 2500-2150-cm(-1) region, and an absorptive behavior in the 2100-1800-cm(-1) region. To fully understand the importance of the hydrogen-bonded chains in the mechanism of the proton transport in bR, a detailed study is carried out here. Comparisons are made between the time-resolved Fourier transform infrared spectroscopy experiments on wild-type bR and its E204Q mutant (which has no early proton release), and between the changes in the continua observed in thermally or photothermally heated water (using visible light-absorbing dye) and those observed during the photocycle. The results strongly suggest that, except for the weak bleach in the 1900-1800-cm(-1) region and >2500 cm(-1), there are other infrared continua observed during the bR photocycle, which are inseparable from the changes in the absorption of the solvent water molecules that are photothermally excited via the nonradiative relaxation of the photoexcited retinal chromophore. A possible structure of the hydrogen-bonded system, giving rise to the observed bleach in the 1900-1800-cm(-1) region and the role of the polarizable proton in the proton transport is discussed.

Citing Articles

Diversity, Mechanism, and Optogenetic Application of Light-Driven Ion Pump Rhodopsins.

Inoue K Adv Exp Med Biol. 2021; 1293:89-126.

PMID: 33398809 DOI: 10.1007/978-981-15-8763-4_6.

Hydration of the Carboxylate Group in Anti-Inflammatory Drugs: ATR-IR and Computational Studies of Aqueous Solution of Sodium Diclofenac.

Levina E, Penkov N, Rodionova N, Tarasov S, Barykina D, Vener M ACS Omega. 2018; 3(1):302-313.

PMID: 30023777 PMC: 6044930. DOI: 10.1021/acsomega.7b01034.

Orientation of non-spherical protonated water clusters revealed by infrared absorption dichroism.

Daldrop J, Saita M, Heyden M, Lorenz-Fonfria V, Heberle J, Netz R Nat Commun. 2018; 9(1):311.

PMID: 29358659 PMC: 5778031. DOI: 10.1038/s41467-017-02669-9.

Time-resolved infrared spectroscopy in the study of photosynthetic systems.

Mezzetti A, Leibl W Photosynth Res. 2016; 131(2):121-144.

PMID: 27678250 DOI: 10.1007/s11120-016-0305-3.

Sul1 and Sul2 sulfate transceptors signal to protein kinase A upon exit of sulfur starvation.

Kankipati H, Rubio-Texeira M, Castermans D, Diallinas G, Thevelein J J Biol Chem. 2015; 290(16):10430-46.

PMID: 25724649 PMC: 4400352. DOI: 10.1074/jbc.M114.629022.

References

Spassov V, Luecke H, Gerwert K, Bashford D . pK(a) Calculations suggest storage of an excess proton in a hydrogen-bonded water network in bacteriorhodopsin. J Mol Biol. 2001; 312(1):203-19. DOI: 10.1006/jmbi.2001.4902. View

Anfinrud P, Han C, Hochstrasser R . Direct observations of ligand dynamics in hemoglobin by subpicosecond infrared spectroscopy. Proc Natl Acad Sci U S A. 1989; 86(21):8387-91. PMC: 298287. DOI: 10.1073/pnas.86.21.8387. View

Rammelsberg R, Huhn G, Lubben M, Gerwert K . Bacteriorhodopsin's intramolecular proton-release pathway consists of a hydrogen-bonded network. Biochemistry. 1998; 37(14):5001-9. DOI: 10.1021/bi971701k. View

Brown L, Sasaki J, Kandori H, Maeda A, Needleman R, Lanyi J . Glutamic acid 204 is the terminal proton release group at the extracellular surface of bacteriorhodopsin. J Biol Chem. 1995; 270(45):27122-6. DOI: 10.1074/jbc.270.45.27122. View

Haupts U, Tittor J, Oesterhelt D . Closing in on bacteriorhodopsin: progress in understanding the molecule. Annu Rev Biophys Biomol Struct. 1999; 28:367-99. DOI: 10.1146/annurev.biophys.28.1.367. View

Riesle J, Oesterhelt D, Dencher N, Heberle J . D38 is an essential part of the proton translocation pathway in bacteriorhodopsin. Biochemistry. 1996; 35(21):6635-43. DOI: 10.1021/bi9600456. View

Heberle J, Dencher N . Surface-bound optical probes monitor protein translocation and surface potential changes during the bacteriorhodopsin photocycle. Proc Natl Acad Sci U S A. 1992; 89(13):5996-6000. PMC: 402125. DOI: 10.1073/pnas.89.13.5996. View

le Coutre J, Tittor J, Oesterhelt D, Gerwert K . Experimental evidence for hydrogen-bonded network proton transfer in bacteriorhodopsin shown by Fourier-transform infrared spectroscopy using azide as catalyst. Proc Natl Acad Sci U S A. 1995; 92(11):4962-6. PMC: 41827. DOI: 10.1073/pnas.92.11.4962. View

Tanimoto T, Furutani Y, Kandori H . Structural changes of water in the Schiff base region of bacteriorhodopsin: proposal of a hydration switch model. Biochemistry. 2003; 42(8):2300-6. DOI: 10.1021/bi026990d. View

10.

Wang J, El-Sayed M . Time-resolved Fourier transform infrared spectroscopy of the polarizable proton continua and the proton pump mechanism of bacteriorhodopsin. Biophys J. 2001; 80(2):961-71. PMC: 1301294. DOI: 10.1016/S0006-3495(01)76075-4. View

11.

Kandt C, Schlitter J, Gerwert K . Dynamics of water molecules in the bacteriorhodopsin trimer in explicit lipid/water environment. Biophys J. 2004; 86(2):705-17. PMC: 1303921. DOI: 10.1016/S0006-3495(04)74149-1. View

12.

Wang J, El-Sayed M . Time-resolved long-lived infrared emission from bacteriorhodopsin during its photocycle. Biophys J. 2002; 83(3):1589-94. PMC: 1302256. DOI: 10.1016/S0006-3495(02)73928-3. View

13.

Song L, El-Sayed M, Lanyi J . Protein catalysis of the retinal subpicosecond photoisomerization in the primary process of bacteriorhodopsin photosynthesis. Science. 1993; 261(5123):891-4. DOI: 10.1126/science.261.5123.891. View

14.

Logunov S, El-Sayed M, Lanyi J . Catalysis of the retinal subpicosecond photoisomerization process in acid purple bacteriorhodopsin and some bacteriorhodopsin mutants by chloride ions. Biophys J. 1996; 71(3):1545-53. PMC: 1233621. DOI: 10.1016/S0006-3495(96)79357-8. View

15.

Luecke H, Schobert B, Richter H, Cartailler J, Lanyi J . Structure of bacteriorhodopsin at 1.55 A resolution. J Mol Biol. 1999; 291(4):899-911. DOI: 10.1006/jmbi.1999.3027. View