3IR8

Red fluorescent protein mKeima at pH 7.0

3IR8 の概要

• エントリーDOI: 10.2210/pdb3ir8/pdb
• 分子名称: Large stokes shift fluorescent protein (2 entities in total)
• 機能のキーワード: beta barrel, fluorescent protein
• 由来する生物種: Montipora sp. 20
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 50206.55

構造登録者

Henderson, J.N.,Osborn, M.F.,Koon, N.,Gepshtein, R.,Huppert, D.,Remington, S.J. (登録日: 2009-08-21, 公開日: 2009-09-08, 最終更新日: 2026-03-18)

主引用文献

Henderson, J.N.,Osborn, M.F.,Koon, N.,Gepshtein, R.,Huppert, D.,Remington, S.J.
Excited state proton transfer in the red fluorescent protein mKeima.
J.Am.Chem.Soc., 131:13212-13213, 2009

PubMed 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.

PubMed: 19708654
DOI: 10.1021/ja904665x

実験手法

X-RAY DIFFRACTION (1.63 Å)