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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The proton and metal binding sites responsible for the pH-dependent green-red bioluminescence color tuning in firefly luciferases

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Author(s):
Viviani, Vadim R. [1] ; Gabriel, Gabriele V. M. [2] ; Bevilaqua, Vanessa R. [2] ; Simoes, A. F. [1] ; Hirano, T. [3] ; Lopes-de-Oliveira, P. S. [4]
Total Authors: 6
Affiliation:
[1] Fed Univ Sao Carlos UFSCar, Grad Program Biotechnol & Environm Monitoring, Rodovia Joao Leme dos Santos, Km 110, Sorocaba, SP - Brazil
[2] Fed Univ Sao Carlos UFSCAR, Grad Program Evolut Genet & Mol Biol, Sao Carlos, SP - Brazil
[3] Tokyo Electrocommun Univ, Tokyo - Japan
[4] CNPEM, Lab Nacl Biociencias LNBio, Campinas, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: SCIENTIFIC REPORTS; v. 8, DEC 4 2018.
Web of Science Citations: 4
Abstract

Firefly luciferases produce yellow-green light under physiological and alkaline conditions, however at acidic pH, higher temperatures or in the presence of heavy metals the color changes to red, a property called pH-sensitivity. Despite many decades of studies, the proton and metal binding sites responsible for pH-sensitivity remain enigmatic. Previously we suggested that the salt bridge E311/R337 keeps a closed conformation of the luciferin phenolate binding site. Here we further investigated the effect of this salt bridge and mutations of the neighbor residues H310 and E/N354, on metal and pH-sensitivity of firefly luciferases emitting distinct bioluminescence colors (Cratomorphus distinctus: 548 nm; Macrolampis sp2: 569 nm). The substitutions of H310 and E/N354 modulate metal sensitivity, whereas the carboxylate of E311 may work as the catalytic base essential for green bioluminescence and pH-sensitivity. Modeling studies showed that H310, E311 and E354 side-chains coordinate Zinc, constituting the metal binding site and the pH-sensor. Electrostatic potential and pKa calculations suggest that the external couple H310/E354 is affected by pH, whereas E311/R337 make a stabilized internal pair which retains excited oxyluciferin ejected proton near its phenolate group into a high energy state, promoting yellow-green bioluminescence. Protonation or metal binding weaken these electrostatic gates and their ability to retain the excited oxyluciferin released proton near its phenolate, promoting red light emission. (AU)

FAPESP's process: 10/05426-8 - Arthropod bioluminescence: biological diversity in Brazilian biomes, biochemical origin, structural/functional evolution of luciferases, molecular differentiation of lanterns, biotechnological, environmental and educational applications
Grantee:Vadim Viviani
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 13/09594-0 - Analysis of coleopteran lanterns, fat body and Malpighian tubules transcriptomes, and its relationship with the origins of bioluminescence in Coleoptera and Diptera
Grantee:Vadim Viviani
Support Opportunities: Regular Research Grants