Mining proteomes for zinc finger persulfidation.

Hydrogen sulfide (H2S) is an endogenous gasotransmitter that signals via persulfidation. There is evidence that the cysteine residues of certain zinc finger (ZF) proteins, a common type of cysteine rich protein, are modified to persulfides by H2S. To determine how frequently ZF persulfidation occurs in cells and identify the types of ZFs that are persulfidated, persulfide specific proteomics data were evaluated. 22 datasets from 16 studies were analyzed via a meta-analysis approach. Persulfidated ZFs were identified in a range of eukaryotic species, including Homo sapiens, Mus musculus, Rattus norvegicus, Arabidopsis thaliana, and Emiliania huxley (single-celled phytoplankton). The types of ZFs identified for each species encompassed all three common ZF ligand sets (4-cysteine, 3-cysteine-1-histidine, and 2-cysteine-2-hisitidine), indicating that persulfidation of ZFs is broad. Overlap analysis between different species identified several common ZFs. GO and KEGG analysis identified pathway enrichment for ubiquitin-dependent protein catabolic process and viral carcinogenesis. These collective findings support ZF persulfidation as a wide-ranging PTM that impacts all classes of ZFs.

Chemoselective Proteomics, Zinc Fingers, and a Zinc(II) Model for H2S Mediated Persulfidation.

The gasotransmitter hydrogen sulfide (H2S) is thought to be involved in the post-translational modification of cysteine residues to produce reactive persulfides. A persulfide-specific chemoselective proteomics approach with mammalian cells has identified a broad range of zinc finger (ZF) proteins as targets of persulfidation. Parallel studies with isolated ZFs show that persulfidation is mediated by ZnII, O2, and H2S, with intermediates involving oxygen- and sulfur-based radicals detected by mass spectrometry and optical spectroscopies. A small molecule ZnII complex exhibits analogous reactivity with H2S and O2, giving a persulfidated product. These data show that ZnII is not just a biological structural element, but also plays a critical role in mediating H2S-dependent persulfidation. ZF persulfidation appears to be a general post-translational modification and a possible conduit for H2S signaling. This work has implications for our understanding of H2S-mediated signaling and the regulation of ZFs in cellular physiology and development.

Hybrid nanospheres of silica covalently containing yellow-emitting cationic iridium(III) complex: preparation and application in white light-emitting diodes.

A yellow-emitting cationic iridium(III) complex [(dfppy)2Ir(TBD)]PF6 (TBD: N4,N4'-bis(3-(triethoxysilyl)propyl)-[2,2'-bipyridine]-4,4'-dicarboxamide; dfppy: 2-(2,4-difluorophenyl)pyridine) containing hydrolysable alkoxysilanes was synthesized. Then, a series of silica-based hybrid nanospheres with diameters of around 400 nm was prepared via the hydrolysis of this complex together with tetraethyl orthosilicate (TEOS, a silica source). When the amount of the complex used was 5.0 wt%, hybrid nanospheres showed the best photoluminescence (PL) properties, relative to the PL quantum yield of pure solid [(dfppy)2Ir(TBD)]PF6 (12.7%), that of hybrid nanospheres increased to 26.2%. Moreover, the thermal decomposition temperature (Td) of pure solid [(dfppy)2Ir(TBD)]PF6 was 331 °C, the Td of the complex in hybrid nanospheres increased to 447 °C. However, the yellow light emission was almost unchanged and was still located at 500-750 nm with a maximum wavelength (λem,max) of 577 nm. Under the excitation of blue-emitting chips (λem,max ≈ 455 nm), cold/neutral/warm white light-emitting diodes (WLEDs) with good luminous quality can all be fabricated using these hybrid nanospheres as phosphors in epoxy resin at different blending concentrations. Compared with two or three iridium(III) complexes being contained in silica-based particles as phosphors as described in literatures, in this study, silica-based hybrid nanospheres covalently containing only one yellow-emitting cationic iridium(III) complex as phosphors provide a more effective and simpler method for preparation high-performance WLEDs.

A cationic iridium(III) complex containing a thiosemicarbazide unit: Synthesis and application for turn-on chemiluminescent detection of Hg2.

A novel cationic iridium(III) complex [(ppy)2Ir(bPCPC)]PF6 (ppy: 2-phenylpyridine; bPCPC: 2-([2,2'-bipyridine]-4-carbonyl)-N-phenylhydrazinecarbothioamide) containing a thiosemicarbazide unit was designed and synthesized. The thiosemicarbazide unit was a sensitive functional group to Hg2+, when it reacted with Hg2+, it was desulphurized and thus led to the formation of 1,3,4-oxadiazole, [(ppy)2Ir(bPCPC)]PF6 resultantly was used as a "turn-on" chemodosimeter for luminescent detection of Hg2+ in DMF/PBS buffer solution at pH = 7-11. Except for Ag+, recognition capability of [(ppy)2Ir(bPCPC)]PF6 to Hg2+ was not interfered by other common metal ions (Co2+, Li+, Zn2+, Pb2+, K+, Al3+, Na+, Mn2+, Cu2+, Fe2+, Fe3+, Cr3+, Ba2+, Mg2+, Ni2+ and Ca2+). The detection limit was 1.83 × 10-9 mol∙L-1 (0.37 ppb), which indicated the complex was a highly sensitive chemiluminescent detection reagent of Hg2+.

Metabolomics Combined with Multivariate Statistical Analysis for Screening of Chemical Markers between Gentiana scabra and Gentiana rigescens.

Gentianae Radix et Rhizome (Longdan in Chinese, GRR) in Chinese Pharmacopoeia is derived from the dried roots and rhizomes of Gentiana scabra and G. rigescens, that have long been used for heat-clearing and damp-drying in the medicinal history of China. However, the characterization of the chemical components of two species and the screening of chemical markers still remain unsolved. In current research, the identification and characterization of chemical components of two species was performed using ultra-high-performance liquid chromatography (UHPLC) coupled with linear ion trap-Orbitrap (LTQ-Orbitrap) mass spectrometry. Subsequently, the chemical markers of two species were screened based on metabolomics and multivariate statistical analysis. In total, 87 chemical constituents were characterized in G. scabra (65 chemical constituents) and G. rigescens (51 chemical constituents), with 29 common chemical constituents being discovered. Thereafter, 11 differential characteristic components which could differentiate the two species were designated with orthogonal partial least squares discriminant analysis (OPLS-DA) and random forest (RF) iterative modeling. Finally, seven characteristic components identified as (+)-syringaresinol, lutonarin, trifloroside, 4-O-ß-d-glu-trifloroside, 4″-O-ß-d-glucopyranosy1-6'-O-(4-O-ß-d-glucaffeoyl)-linearroside, macrophylloside a and scabraside were selected as the chemical markers for the recognition of two Gentiana species. It was implied that the results could distinguish the GRR derived from different botanical sources, and also be beneficial in the rational clinical use of GRR.