Bacterial luciferase reaction mechanism

Macheroux, R, Ghisla, S., Kurfiirst, M., and Hastings, J.W., Studies on the bacterial luciferase reaction isotope effects on the Hght emission. Is a CIEEL mechanism involved , in Flavins and Flavoproteins, Bray, R.C., Engel, PC., and Mayhew, S.G., Eds., Walter deGruyter, Berlin, 1984, p. 669. 

Francisco, W.A., Abu-Soud, H.M., DelMonte, A.J., Singleton, D.A., Baldwin, TO., and Raushel, F.M., Deuterium kinetic isotope effects and the mechanism of the bacterial luciferase reaction. 

Fig. 2.1 Mechanism of the bacterial bioluminescence reaction. The molecule of FMNH2 is deprotonated at N1 when bound to a luciferase molecule, which is then readily peroxidized at C4a to form Intermediate A. Intermediate A reacts with a fatty aldehyde (such as dodecanal and tetradecanal) to form Intermediate B. Intermediate B decomposes and yields the excited state of 4a-hydroxyflavin (Intermediate C) and a fatty acid. Light (Amax 490 nm) is emitted when the excited state of C falls to the ground state. The ground state C decomposes into FMN plus H2O. All the intermediates (A, B, and C) are luciferase-bound forms. The FMN formed can be reduced to FMNH2 in the presence of FMN reductase and NADH.

Eckstein, J. W., and Ghisla, S. (1991). On the mechanism of bacterial luciferase. 4a,5-Dihydroflavins as model compounds for reaction intermediates. In Flavins Flavoproteins, Proc. Int. Symp., 10th, 1990, 269-272. 

At least five detailed mechanisms have been proposed for bacterial luciferase within the last six years (28, 47, 48, 49, 50). With the assumption that our biomimetic model relates to the enzyme-catalyzed reaction, we conclude that these five proposals of mechanisms are incorrect. Four (28, 47,48) are inconsistent with the intermediacy of the mixed peroxide (4a-FlEt—O—O—CH(OH)R ) and cannot be applied to N(5)-alkylflavins. In addition, two (28, 47) of these mechanisms as well as another (49), require the hydroxyl group of the aldehyde-peroxide adduct. No mechanism can be taken seriously without the identification of the excited species. We do know that a hydrogen substituted is required on the carbon that is converted to a carbonyl group (47). 

The reaction mechanism of bacterial luciferase has been studied extensively.1 2 An electron-exchange reaction mechanism (Scheme l)3 4 has been postulated and gained considerable acceptance. 

Fig. 180. Postulated reaction mechanism catalyzed by bacterial luciferase...

Holzman, T.F. and Baldwin, T.O., Reversible inhibition of the bacterial luciferase catalyzed bioluminescence reaction by aldehyde substrate kinetic mechanism and Ugand effects. Biochemistry, 22, 2838, 1983. 

The mechanisms of inhibition/stimulation of bacterial luminescence are not fully understood. A luciferase-flavin adduct is formed in an excited state and the excess of energy is then released in the form of visible light (Nakamura et al. 1982). Any substance able to interfere in one or more steps of this reaction, as shown by reduced light emission, is classified as toxic. Also, a substance which may interact with any of the other biochemical functions of the bacteria, resulting in the death or a reduced metabolic activity of the organisms is... 

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