Synthesis and properties of the chromophore of the asFP595 chromoprotein from Anemonia sulcata.
A model compound for the chromophore within the purple nonfluorescent GFP-like chromoprotein asFP595 was synthesized. The postulated structure of the chromophore, 2-acetyl-4-(p-hydroxybenzylidene)-1-methyl-5-imidazolone, was taken from the high-resolution crystal structure analysis of intact asFP595 [Quillin, M. L., Anstrom, D., Shu, X., O'Leary, S., Kallio, K., Lukyanov, K. A., and Remington, S. J. (2005) Kindling Fluorescent Protein from Anemonia sulcata: Dark-State Structure at 1.38 A Resolution, Biochemistry 44, 5774-5787]. Erlenmeyer lactonization and oxidation of the methylene group attached to the heteroaromatic moiety with selenium dioxide were used at the key stages of the synthesis. The spectral properties of the model chromophore in solution and their dependence on the pH and polarity of the solvent were investigated. In water, the chromophore was found to exist in two forms, neutral and anionic, with a pK(a) of 7.1. In a dimethylformamide solution, the spectral properties of the anionic form closely match those of the native protein, demonstrating that under these conditions, the compound is an excellent model for the chromophore within native asFP595.
Yampolsky
Ilia V
IV
Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia.
Remington
S James
SJ
Martynov
Vladimir I
VI
Potapov
Victor K
VK
Lukyanov
Sergey
S
Lukyanov
Konstantin A
KA
D000818:Animals; D006863:Hydrogen-Ion Concentration; D008164:Luminescent Proteins / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D012615:Sea Anemones / Q000737:chemistry*; D013053:Spectrophotometry; D014867:Water
D008164:Luminescent Proteins; D014867:Water