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Excited state proton transfer in the red fluorescent protein mKeima.
J Am Chem Soc 2009; 131(37):13212-3JA

Abstract

mKeima is an unusual monomeric red fluorescent protein (lambda(em)(max) approximately 620 nm) that is maximally excited in the blue (lambda(ex)(max) approximately 440 nm). The large Stokes shift suggests that the chromophore is normally protonated. A 1.63 A resolution structure of mKeima reveals the chromophore to be imbedded in a novel hydrogen bond network, different than in GFP, which could support proton transfer from the chromophore hydroxyl, via Ser142, to Asp157. At low temperatures the emission contains a green component (lambda(em)(max) approximately 535 nm), enhanced by deuterium substitution, presumably resulting from reduced proton transfer efficiency. Ultrafast pump/probe studies reveal a rising component in the 610 nm emission with a lifetime of approximately 4 ps, characterizing the rate of proton transfer. Mutation of Asp157 to neutral Asn changes the chromophore resting charge state to anionic (lambda(ex)(max) approximately 565 nm, lambda(em)(max) approximately 620 nm). Thus, excited state proton transfer (ESPT) explains the large Stokes shift. This work unambiguously characterizes green emission from the protonated acylimine chromophore of red fluorescent proteins.

Authors+Show Affiliations

Institute of Molecular Biology and Department of Physics, University of Oregon, Eugene, Oregon 97403-1229, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19708654

Citation

Henderson, J Nathan, et al. "Excited State Proton Transfer in the Red Fluorescent Protein MKeima." Journal of the American Chemical Society, vol. 131, no. 37, 2009, pp. 13212-3.
Henderson JN, Osborn MF, Koon N, et al. Excited state proton transfer in the red fluorescent protein mKeima. J Am Chem Soc. 2009;131(37):13212-3.
Henderson, J. N., Osborn, M. F., Koon, N., Gepshtein, R., Huppert, D., & Remington, S. J. (2009). Excited state proton transfer in the red fluorescent protein mKeima. Journal of the American Chemical Society, 131(37), pp. 13212-3. doi:10.1021/ja904665x.
Henderson JN, et al. Excited State Proton Transfer in the Red Fluorescent Protein MKeima. J Am Chem Soc. 2009 Sep 23;131(37):13212-3. PubMed PMID: 19708654.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Excited state proton transfer in the red fluorescent protein mKeima. AU - Henderson,J Nathan, AU - Osborn,Maire F, AU - Koon,Nayden, AU - Gepshtein,Rinat, AU - Huppert,Dan, AU - Remington,S James, PY - 2009/8/28/entrez PY - 2009/8/28/pubmed PY - 2010/1/6/medline SP - 13212 EP - 3 JF - Journal of the American Chemical Society JO - J. Am. Chem. Soc. VL - 131 IS - 37 N2 - mKeima is an unusual monomeric red fluorescent protein (lambda(em)(max) approximately 620 nm) that is maximally excited in the blue (lambda(ex)(max) approximately 440 nm). The large Stokes shift suggests that the chromophore is normally protonated. A 1.63 A resolution structure of mKeima reveals the chromophore to be imbedded in a novel hydrogen bond network, different than in GFP, which could support proton transfer from the chromophore hydroxyl, via Ser142, to Asp157. At low temperatures the emission contains a green component (lambda(em)(max) approximately 535 nm), enhanced by deuterium substitution, presumably resulting from reduced proton transfer efficiency. Ultrafast pump/probe studies reveal a rising component in the 610 nm emission with a lifetime of approximately 4 ps, characterizing the rate of proton transfer. Mutation of Asp157 to neutral Asn changes the chromophore resting charge state to anionic (lambda(ex)(max) approximately 565 nm, lambda(em)(max) approximately 620 nm). Thus, excited state proton transfer (ESPT) explains the large Stokes shift. This work unambiguously characterizes green emission from the protonated acylimine chromophore of red fluorescent proteins. SN - 1520-5126 UR - https://www.unboundmedicine.com/medline/citation/19708654/Excited_state_proton_transfer_in_the_red_fluorescent_protein_mKeima_ L2 - https://dx.doi.org/10.1021/ja904665x DB - PRIME DP - Unbound Medicine ER -