Mutagenesis Evidence that the Partial Reactions of Firefly Bioluminescence Are Catalyzed by Different Conformations of the Luciferase C-Terminal Domain Export

@article{Branchini05, abstract = {Abstract: Firefly luciferase catalyzes two sequential partial reactions resulting in the emission of light. The enzyme first catalyzes the adenylation of substrate luciferin with Mg-ATP followed by the multistep oxidation of the adenylate to form the light emitter oxyluciferin in an electronically excited state. The beetle luciferases are members of a large superfamily, mainly comprised of nonbioluminescent enzymes that activate carboxylic acid substrates to form acyl-adenylate intermediates. Recently, the crystal structure of a member of this adenylate-forming family, acetyl-coenzyme A (CoA) synthetase, was determined in complex with an unreactive analogue of its acyl-adenylate and CoA [Gulick, A. M., Starai, V. J., Horswill, A. R., Homick, K. M., and Escalante-Semerena, J. C. (2003) Biochemistry 42, 2866-2873]. This structure presented a new conformation for this enzyme family, in which a significant rotation of the C-terminal domain brings residues of a conserved -hairpin motif to interact with the active site. We have undertaken a mutagenesis approach to study the roles of key residues of the equivalent -hairpin motif in Photinus pyralis luciferase (442IleLysTyrLysGlyTyrGlnVal449) in the overall production of light and the individual adenylation and oxidation partial reactions. Our results strongly suggest that Lys443 is critical for efficient catalysis of the oxidative half-reaction. Additionally, we provide evidence that Lys443 and Lys529, located on opposite sides of the C-terminal domain and conserved in all firefly luciferases, are each essential for only one of the partial reactions of firefly bioluminescence, supporting the proposal that the superfamily enzymes may adopt two different conformations to catalyze the two half-reactions.}, address = {Department of Chemistry, Connecticut College, New London, Connecticut 06320}, author = {Branchini, B. R. and Southworth, T. L. and Murtiashaw, M. H. and Wilkinson, S. R. and Khattak, N. F. and Rosenberg, J. C. and Zimmer, M.}, citeulike-article-id = {1572646}, citeulike-linkout-0 = {http://dx.doi.org/10.1021/bi047903f}, citeulike-linkout-1 = {http://pubs.acs.org/doi/abs/10.1021/bi047903f}, day = {8}, doi = {10.1021/bi047903f}, journal = {Biochemistry}, keywords = {kinetics, luciferase, reaction}, month = {February}, number = {5}, pages = {1385--1393}, posted-at = {2007-08-17 16:55:27}, priority = {2}, title = {Mutagenesis Evidence that the Partial Reactions of Firefly Bioluminescence Are Catalyzed by Different Conformations of the Luciferase C-Terminal Domain}, url = {http://dx.doi.org/10.1021/bi047903f}, volume = {44}, year = {2005} }

TY - JOUR ID - Branchini05 L3 - citeulike-article-id:1572646 N2 - Abstract: Firefly luciferase catalyzes two sequential partial reactions resulting in the emission of light. The enzyme first catalyzes the adenylation of substrate luciferin with Mg-ATP followed by the multistep oxidation of the adenylate to form the light emitter oxyluciferin in an electronically excited state. The beetle luciferases are members of a large superfamily, mainly comprised of nonbioluminescent enzymes that activate carboxylic acid substrates to form acyl-adenylate intermediates. Recently, the crystal structure of a member of this adenylate-forming family, acetyl-coenzyme A (CoA) synthetase, was determined in complex with an unreactive analogue of its acyl-adenylate and CoA [Gulick, A. M., Starai, V. J., Horswill, A. R., Homick, K. M., and Escalante-Semerena, J. C. (2003) Biochemistry 42, 2866-2873]. This structure presented a new conformation for this enzyme family, in which a significant rotation of the C-terminal domain brings residues of a conserved -hairpin motif to interact with the active site. We have undertaken a mutagenesis approach to study the roles of key residues of the equivalent -hairpin motif in Photinus pyralis luciferase (442IleLysTyrLysGlyTyrGlnVal449) in the overall production of light and the individual adenylation and oxidation partial reactions. Our results strongly suggest that Lys443 is critical for efficient catalysis of the oxidative half-reaction. Additionally, we provide evidence that Lys443 and Lys529, located on opposite sides of the C-terminal domain and conserved in all firefly luciferases, are each essential for only one of the partial reactions of firefly bioluminescence, supporting the proposal that the superfamily enzymes may adopt two different conformations to catalyze the two half-reactions. IS - 5 JF - Biochemistry AD - Department of Chemistry, Connecticut College, New London, Connecticut 06320 EP - 1393 TI - Mutagenesis Evidence that the Partial Reactions of Firefly Bioluminescence Are Catalyzed by Different Conformations of the Luciferase C-Terminal Domain VL - 44 SP - 1385 KW - kinetics KW - luciferase KW - reaction AU - Branchini, BR AU - Southworth, TL AU - Murtiashaw, MH AU - Wilkinson, SR AU - Khattak, NF AU - Rosenberg, JC AU - Zimmer, M PY - 2005/02/08/ UR - http://dx.doi.org/10.1021/bi047903f ER -