Abstract
The binding of the semiquinone to its two position (proximal and distal) in the QB site of the bacterial photosynthetic reaction center of Rhodobacter sphaeroides, was studied using continuum electrostatics. Experimental determined populations of the semiquinone in the proximal positions could be reproduced. Residues influencing either the binding of the semiquinone or the popluation of the semiquinone in the proximal position, could be identified. Both, the population and the binding of the semiquinone to the QB site is coupled to the protonation state of AspL213, which is located in direct vicinity of the semiquinone. Our results show, that a protonated AspL213 stabilizes the binding of the semiquinone and it favors the proximal position.
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References
Bashford D, Gerwert K (1992) Electrostatic calculations of the pKa values of ionizable groups in bacteriorhodopsin. J Mol Biol 224:4734-4786.
Koepke J, Krammer E-M, Klingen AR, Sebban P, Ullmann GM, Fritzsch (2007) pH modulates the quinone position in the photosynthetic reaction center from Rhodobacter sphaeroides in the neutral and charge separated states. J Mol Biol 371:396-409.
Paddock ML, Feher G, Okamura MY (2003) Proton transfer pathways and mechanism in bacterial reaction centers. FEBS Lett 555:45-50.
Rongley SH, Paddock ML, Feher G, Okamura MY (1993) Pathway of proton transfer in bacterial reaction centers: Second-site mutation AsnM44- > Asp restores electron and proton transfer in reaction centers from the photosynthetically deficient AspL213- > Asn mutant of Rhodobacter sphaeroides. Proc Natl Acad Sci USA 90:1325-1329.
Stowell MHV, McPhillips DC, Rees SM, Soltis E, Abresch E, Feher G (1997) Light-induced structural changes in the photosynthetic reaction center: implications for mechanism of electron-proton transfer. Science 276:812-816.
Ullmann GM, Knapp E-W (1999) Electrostatic models for computing protonation and redox equilibria in proteins. Eur Biophys J 28:533-551.
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© 2008 Springer Science + Business Media, B.V.
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Krammer, EM., Ullmann, G.M. (2008). The Role of AspL213 for Stabilizing Semiquinone Binding to the Photosynthetic Reaction Center. In: Allen, J.F., Gantt, E., Golbeck, J.H., Osmond, B. (eds) Photosynthesis. Energy from the Sun. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-6709-9_29
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DOI: https://doi.org/10.1007/978-1-4020-6709-9_29
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-6707-5
Online ISBN: 978-1-4020-6709-9
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