Spectral tuning of obelin bioluminescence by mutations of Trp92.
The Ca(2+)-regulated photoprotein obelin was substituted at Trp92 by His, Lys, Glu, and Arg. All mutants fold into stable conformations and produce bimodal bioluminescence spectra with enhanced contribution from a violet emission. The W92R mutant has an almost monomodal bioluminescence (lambdamax=390 nm) and monomodal fluorescence (lambdamax=425 nm) of the product. Results are interpreted by an excited state proton transfer mechanism involving the substituent side group and His22 in the binding cavity.
Photobiology Lab, Institute of Biophysics, Russian Academy of Sciences Siberian Branch, Krasnoyarsk 660036, Russia.
Natalia P
NP
Malikova
Galina A
GA
Stepanyuk
Ludmila A
LA
Frank
Svetlana V
SV
Markova
Eugene S
ES
Vysotski
John
J
Lee
D019943:Amino Acid Substitution; D002118:Calcium / Q000032:analysis; D005453:Fluorescence; D049449:Luminescence; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics; D015335:Molecular Probes; D016297:Mutagenesis, Site-Directed; D013057:Spectrum Analysis; D014364:Tryptophan
D008164:Luminescent Proteins; D015335:Molecular Probes; C010497:obelin; D014364:Tryptophan; D002118:Calcium