Control of the Ca2+ dependent luminescence of lumisomes by monovalent cations (original) (raw)
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Control of the Ca2+-triggered bioluminescence of Veretillum cynomorium lumisomes
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1978
Calcium ions can trigger an emission of light from Veretillum cynomorium lumisomes (bioluminescent vesicles) under conditions where they are not lysed. This process does not require a metabolically-linked source of energy, but is dependent upon the nature of the ions present inside and outside the vesicles. The Ca2+-triggered bioluminescence is stimulated by an asymmetrical distribution of cations or anions. Either high internal sodium or high external chloride is required for the maximal effect. When sodium is present outside the structure and potassium inside, the slow inward diffusion of calcium is decreased. Unbalanced diffusion of internal cations also stimulates the bioluminescence, suggesting control of the calcium influx by an electrochemical gradient. It is assumed that rapid outward diffusion of sodium or inward diffusion of chloride generates an electrical potential difference (inside negative) which drives the Ca2+-influx. With purified lumisomes it has been shown that Ca2+-triggered bioluminescence and calcium uptake (presumably net uptake)were correlated. In two instances uptake of the lipophilic cation dibenzyldimethylammonium has given direct evidence for the existence of a potential difference. With NaCl-loaded vesicles, it has not been possible to demonstrate an uptake of lipophilic cations but experiments with 22Na and 42K indicated a higher rate of sodium efflux, in accord with the proposed hypothesis.
Febs Journal, 2005
The effect of CoA on the characteristic light decay of the firefly luciferase catalysed bioluminescence reaction was studied. At least part of the light decay is due to the luciferase catalysed formation of dehydroluciferyl-adenylate (L-AMP), a by-product that results from oxidation of luciferyl-adenylate (LH2-AMP), and is a powerful inhibitor of the bioluminescence reaction (IC50 = 6 nm). We have shown that the CoA induced stabilization of light emission does not result from an allosteric effect but is due to the thiolytic reaction between CoA and L-AMP, which gives rise to dehydroluciferyl-CoA (L-CoA), a much less powerful inhibitor (IC50 = 5 µm). Moreover, the Vmax for L-CoA formation was determined as 160 min−1, which is one order of magnitude higher than the Vmax of the bioluminescence reaction. Results obtained with CoA analogues also support the thiolytic reaction mechanism: CoA analogues without the thiol group (dethio-CoA and acetyl-CoA) do not react with L-AMP and do not antagonize its inhibitor effect; CoA and dephospho-CoA have free thiol groups, both react with L-AMP and both antagonize its effect. In the case of dephospho-CoA, it was shown that it reacts with L-AMP forming dehydroluciferyl-dephospho-CoA. Its slower reactivity towards L-AMP explains its lower potency as antagonist of the inhibitory effect of L-AMP on the light reaction. Moreover, our results support the conjecture that, in the bioluminescence reaction, the fraction of LH2-AMP that is oxidized into L-AMP, relative to other inhibitory products or intermediates, increases when the concentrations of the substrates ATP and luciferin increases.
Photochemistry and photobiology, 2016
Upon binding their metal ion cofactors, Ca(2+) -regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca(2+) -regulated photoproteins-aequorin from Aequorea victoria, clytin from Clytia gregaria, mitrocomin from Mitrocoma cellularia and obelins from Obelia longissima and Obelia geniculata-demonstrate the same bioluminescent kinetics pattern. Based on these findings, for the first time we propose a unanimous kinetic model describing the bioluminescence mechanism of Ca(2+) -regulated photoproteins.
Selected Least Studied but not Forgotten Bioluminescent Systems
Photochemistry and photobiology, 2016
Bioluminescence is a form of chemiluminescence generated by luminous organisms. Luminous taxa have currently been reported from about 800 genera and probably over 10,000 species in the world. On the other hand, their bioluminescent systems, including chemical structures of luciferins/chromophores and the genes encoding luciferases/photoproteins, have been elucidated from only a few taxonomic groups; e.g. beetles, bacteria, dinoflagellates, ostracods, and some cnidarians. Research efforts to understand unknown bioluminescence systems are being conducted around the world, and recently, for example, novel luciferin structures of luminous enchytraeid potworms and fungi were identified by the authors. In this paper, we review the current status and perspectives, in the context of post-genomic era, of most-likely novel but less-revealed bioluminescence systems of ten selected organisms; earthworm, parchment tubeworm, fireworm, scaleworm, limpet, millipede, brittle star, acorn worms, tunic...
The theoretical studies of light emitters in bioluminescence of Ca-regulated photoprothin obelin
2008
ATP is the major source for metabolic energy in the cell and affects numerous cellular processes. Generally ATP is measured by luminescence assay using firefly luciferin-luciferase reaction as total ATP content in a mass of cells. We developed a luminescence microscope to measure ATP at the single cell level and applied it to monitor cytosolic ATP level throughout the apoptotic process in a HeLa cell transfected luciferase gene. As a result, apoptotic stimuli by four medicines (staurosporine, carbonyl cyanide p-trifluoro-methoxyphenylhydrazone, cycloheximide and actinomycin D) induced elevation of the ATP level after 1-2 h. This result confirmed previous data reported by luminometric assay. However, we observed a phenomenon just before cell death that some cells emit flash luminescence after 4-8 h stimulus. It is uncertain whether or not the flash luminescence is due to increased cytosolic ATP; such a result can not be obtained by conventional luminometric assay. The bioluminescence imaging assay at the cellular level would make a new research field, not only in ATP measurement but also in intracellular signal transduction, regulation of gene expression and other areas.
Ca 2+ -Regulated Photoproteins: Structural Insight into the Bioluminescence Mechanism
Accounts of Chemical Research, 2004
The bioluminescent jellyfish has contributed two famous proteins to modern science: green fluorescent protein or GFP, which finds wide use as a probe in cell biology studies, and aequorin, which has been used for intracellular calcium measurement for more than 30 years. More recently, obelin, a protein from the bioluminescent hydroid and also in the family of what are called "Ca 2+ -regulated photoproteins", has been shown to have very attractive properties both in general applications and for basic structural biology investigations. This review will survey the new information into their molecular mechanism of bioluminescence action. † Russian Academy of Sciences, Siberian Branch.