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.
Malikova
Natalia P
NP
Photobiology Lab, Institute of Biophysics, Russian Academy of Sciences Siberian Branch, Krasnoyarsk 660036, Russia.
Stepanyuk
Galina A
GA
Frank
Ludmila A
LA
Markova
Svetlana V
SV
Vysotski
Eugene S
ES
Lee
John
J
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