Revealing the involvement of extended hydrogen bond networks in the cooperative function between distant sites in bacterial reaction centers

The Journal of Biological Chemistry
Julia TandoriP Sebban

Abstract

In reaction center proteins of photosynthetic bacteria, the amplitude of proton uptake induced by the one-electron reduction of either of the two quinone electron acceptors (Q(A) and Q(B)) is an intrinsic observable of the electrostatic interactions associated with the redox function of the complex. We report here that, in Rhodobacter capsulatus, complete restoration of proton uptake (upon formation of Q(A)(-) and Q(B)(-)) to the level found in the wild type is observed in a mutant reaction center in which a tyrosine substitution in the Q(A) environment (Ala(M274) --> Tyr) is coupled with mutations of acidic residues near Q(B) (Glu(L212) --> Ala/Asp(L213) --> Ala) that initially cancel the proton uptake above pH 8. This result demonstrates that proton uptake occurs by strong cooperation between structural motifs, such as hydrogen-bonded networks, that span the 18 A distance between the two quinone acceptors.

References

Oct 1, 1993·Proceedings of the National Academy of Sciences of the United States of America·D K HansonM Schiffer
Dec 1, 1995·Nature Structural Biology·P MarótiP Sebban

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Citations

Jun 25, 2004·The Journal of Membrane Biology·J L Johnson, R J Brooker
Feb 22, 2012·Biochemistry. Biokhimii︠a︡·M M LeonovaV A Shuvalov
Mar 9, 2002·Photochemistry and Photobiology·Julia TandoriPierre Sebban
May 2, 2002·Proceedings of the National Academy of Sciences of the United States of America·J TandoriL Baciou
Jan 22, 2015·Biophysical Journal·László GerencsérPéter Maróti
Mar 25, 2009·Biochimica Et Biophysica Acta·Anne Pilotelle-BunnerPierre Sebban

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