THE COMPLEXES FORMED BY BILADIENE a, b COMPOUNDS WITH ZINC IONS and THEIR APPLICATION IN DETERMINATION OF THE CHROMOPHORE COMPOSITION OF α‐ and β‐ SUBUNITS OF R‐PHYCOERYTHRIN

Abstract

Abstract— –Phycoerythrobilin dimethyl ester (PEBDM) or isomesobiliviolin dimethyl ester (IBVDM) formed complexes with zinc ions in chloroform. The complex ratios were determined to be 1:1 according to the spectrophotometric titration of PEBDM and IBVDM with zinc ions in methanol and the mass spectra of the complexes. The chromophore compositions of R‐phycoerythrin from Porphyra yezoensis were determined by spectrophotometric titration of α‐ and β‐subunits at pH 13.0 with zinc ions. There were 2 phycoerythrobilins in the a‐subunit, and 1 phycourobilin and 3 phycoerythrobilins in the β‐subunit.

Dual emission from nanoconfined R-phycoerythrin fluorescent proteins for white light emission diodes

“…It has been proven that aer the formation of complexes PEB-Zn and PUB-Zn, with a tetrahedral structure of which the Zn ion is located at the center, the energy of the p* orbital decreased, and the p / p* and n / p* absorptions were redshied. 26,27,29,[43][44][45] The absorption wavelength maximum of PUB was shied to 509 nm, which is consistent with that of PUB-Zn salts reported in the literature (509 nm). The absorption wavelength maximum of PEB shied to 597 nm and is also close to that of PEB-Zn salts reported in the literature (583 nm), 43 indicating the formation of complexes PEB-Zn and PUB-Zn.…”

“…1d-f) show that the sulfur element from the thio-ether bonds of the R-PE proteins is evenly distributed in the ZIF-8 crystals. 29 This indicates that the R-PE proteins are uniformly encapsulated and well distributed Scheme 1 Schematic illustration of the synthesis process of the R-PE/ QDs@ZIF-8 thin films on quartz. in the ZIF-8 thin lm.…”

“…In pH 6.8 and 0.1 M phosphate buffer, R-PE emitted strong uorescence at 578 nm due to the energy transfer between PEB and PUB. 28,29 If the energy transfer between PEB and PUB is impeded, 26 it is possible to produce dual color emissions from R-PE proteins.…”

“…This is probably because the polypeptide structures of R-PE are pulled apart due to electrostatic-assisted assembly along the ZHNs, and the formation of PEB-Zn and PUB-Zn complexes. 26,27,29,[43][44][45] The resultant R-PE/QDs@ZIF-8 thin lm exhibits a high photoluminescence quantum yield (PLQY) of 29.8% as R-PE and the QDs are well isolated in the ZIF-8 thin lm, which restricts aggregation-caused PL quenching. 4,5 What's more, the prepared thin lm was processed into a highquality warm-white LED with ideal CIE coordinates of (0.34, 0.34), a high CRI value of 85 and a moderate CCT value of 4955 K. This process provides a new method to manipulate the uorescence colors and enhance the thermal stability of FP based-thin lms for WLEDs.…”

“…It has been reported that the vanish of around 510 nm emission but the enhancement of 578 nm emission of the R-PE solution is due to the energy transfer from PUB to PEB. 28,29,47 Therefore, the maximum emission peak of the R-PE@ZIF-8 thin lms at 518 nm was probably because ZIF-8 pulls the polypeptide structure of the R-PE molecules apart, and the energy transfer between PEB and PUB was thus blocked. 26 Furthermore, the rigid structure of the R-PE proteins became loose during this process, so that it was much easier for the Zn ions to get into the proteins and react with the chromophores including PEB and PUB.…”