Sandbox Reserved 1731

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This Sandbox is Reserved from August 30, 2022 through May 31, 2023 for use in the course Biochemistry I taught by Kimberly Lane at the Radford University, Radford, VA, USA. This reservation includes Sandbox Reserved 1730 through Sandbox Reserved 1749.

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Contents 1 Photinus pyralis luciferase 2 Structure 3 Function 4 Biology 5 References

Photinus pyralis luciferase

spinqualitylabelsall models Structure of Photinus pyralis luciferase (PDB entry 1lci) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Luciferases are enzymes that catalyzes the light-producing chemical reactions of bioluminescent organisms, such as fireflies and bacteria. Photinus pyralis luciferase, which is the specific luciferase protein found in the common eastern firefly, causes an enzymatic reaction between the enzyme (luciferase) and the substrate (luciferin). This reaction is an oxidation process with molecular oxygen and its conversion into chemical energy, which causes the bursts of light ¹.

Structure

The overall structure of luciferase is an asymmetrical monomer. It is composed of two domains specified as the N-terminal and C-terminal. The consists of a beta-barrel and two beta-sheets flanked by alpha-helices to form a five layer structure α-β-α-β-α structure. The consists of five beta-strands and three alpha-helices, which is folded into a compact structure that is connected to the N-terminus domain by a disordered loop. A beta barrel is one singular beta sheet, where the beta strands run antiparallel to one another. Luciferase is composed of 550 amino acids residues in a single polypeptide chain with a peroxisome targeting signal sequence of -Ser-Lys-Leu (-SKL) at C-terminus. The overall structure of luciferase contains ².

Function

Luciferase proteins act as enzymes to to produce bursts of light through oxidation reactions of the substrate, luciferin. The reaction formula is:

ATP + firefly D-luciferin + O₂ ↔ AMP + CO₂ + diphosphate + firefly oxyluciferin + hnu ³

The reaction begins with the formation of an acid anhydride between the carboxylic group of D-firefly luciferin and AMP, with the release of diphosphate. An oxygenation follows, with the release of the AMP group group and formation of a very short-lived peroxide that cyclizes into a dioxetanone structure, which collapses, releasing a CO2 molecule. The spontaneous breakdown of the dioxetanone (rather than the hydrolysis of the hydrolysis of the adenylate) releases the energy (about 50 kcal/mole) that is necessary to generate the excited state of oxyluciferin. The excited luciferin then emits a photon or light (hnu), returning to its ground state. The enzyme has a secondary acyl-CoA ligase activity when acting on L-firefly luciferin ^{4 5}.

Biology

Bioluminescence provides a variety of benefits to the many different organisms who utilize it, such as multiple kinds of bacteria and species of firefly. The eastern common firefly (Photonis pyralis) utilize the bioluminescent characteristic in mating. They are nocturnal as a species use a discrete pulse of bioluminescence to locate their mates during the night. Both sexes of the species produce flash signals that are timed precisely to relay information about the insects species identity and sex. The brightness of the bioluminescent pulse is dependent on the amount of ATP in the cells. If the insect is not producing enough ATP in the cells, the pulses of light will be duller ⁶.

References

1. de Wet, J. R.; Wood, K. V.; Helinski, D. R.; DeLuca, M. Cloning of Firefly Luciferase Cdna and the Expression of Active Luciferase in Escherichia Coli. Proc. Natl. Acad. Sci. U.S.A. 1985, 82 (23), 7870–7873.

2. Baldwin, T. O. Firefly Luciferase: The Structure Is Known, but the Mystery Remains. J. Am. Chem. Soc. 1996, 4 (3), 223–228.

3. de Wet, J. R.; Wood, K. V.; DeLuca, M.; Helinski, D. R.; Subramani, S. Firefly Luciferase Gene: Structure and Expression in Mammalian Cells. Mol. Cell. Biol. 1987, 7 (2), 725–737.

4. Inouye, S. Firefly Luciferase: An Adenylate-Forming Enzyme for Multicatalytic Functions. Cell. Mol. Life. Sci. 2009, 67 (3), 387–404.

5. Marques, S. M.; Esteves da Silva, J. C. Firefly Bioluminescence: A Mechanistic Approach of Luciferase Catalyzed Reactions. IUBMB. Life. 2009, 61 (1), 6–17.

6. Lewis, S. M.; Cratsley, C. K. Flash Signal Evolution, Mate Choice, and Predation in Fireflies. Annu. Rev. Entomol. 2008, 53 (1), 293–321.

7. Tinikul, R.; Chaiyen, P. Structure, Mechanism, and Mutation of Bacterial Luciferase. Adv. Biochem. Eng. Biotechnol. 2016, 154 (3), 47-74.