title: Luciferin-Regenerating Enzyme Crystal Structure Is Solved but its Function Is Still Unclear.
abstract: Contribution of luciferin-regenerating enzyme (LRE) for in vitro recycling of D-luciferin has been reported. According to crystal structure of LRE, it is a beta-propeller protein which is a type of all β-protein architecture. In this overview, reinvestigation of the luciferase-based LRE assays and its function is reported. Until now, sequence of LRE genes from four different species of firefly has been reported. In spite of previous reports, T-LRE (from Lampyris turkestanicus) was cloned and expressed in Escherichia coli as well as Pichia pastoris in a nonsoluble form as inclusion body. According to recent investigations, bioluminescent signal of soluble T-LRE-luciferase-coupled assay increased and then reached an equilibrium state in the presence of D-cysteine. In addition, the results revealed that both D- and L-cysteine in the absence of T-LRE caused a significant increase in bioluminescence intensity of luciferase over a long time. Based on activity measurements and spectroscopic results, D-cysteine increased the activity of luciferase due to its redox potential and induction of conformational changes in structure and kinetics properties. In conclusion, in spite of previous reports on the effect of LRE (at least T-LRE) on luciferase activity, most of the increase in luciferase activity is caused by direct effect of D-cysteine on structure and activity of firefly luciferase. Moreover, bioinformatics analysis cannot support the presence of LRE in peroxisome of photocytes in firefly lanterns.
authors.affiliation: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Saman
authors.initials: S
authors.lastname: Hosseinkhani
authors.affiliation: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Elaheh
authors.initials: E
authors.lastname: Emamgholi Zadeh
authors.affiliation: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Sahebazzamani
authors.affiliation: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Farangis
authors.initials: F
authors.lastname: Ataei
authors.affiliation: Department of Biology, Faculty of Basic Sciences, Shahrekord University, Shahrekord, Iran.
authors.forename: Roohullah
authors.initials: R
authors.lastname: Hemmati
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D048888:Fireflies / Q000201:enzymology; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008025:Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D049449:Luminescence; D010084:Oxidation-Reduction; D010843:Pichia / Q000235:genetics; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D019476:Insect Proteins; D011994:Recombinant Proteins; D008025:Ligases; C471161:luciferin-regenerating enzyme, insect; D003545:Cysteine