Mitochondrial ATP synthase as a direct molecular target of chromium(III) to ameliorate hyperglycaemia stress.

Chromium(III) is extensively used as a supplement for muscle development and the treatment of diabetes mellitus. However, its mode of action, essentiality, and physiological/pharmacological effects have been a subject of scientific debate for over half a century owing to the failure in identifying the molecular targets of Cr(III). Herein, by integrating fluorescence imaging with a proteomic approach, we visualized the Cr(III) proteome being mainly localized in the mitochondria, and subsequently identified and validated eight Cr(III)-binding proteins, which are predominately associated with ATP synthesis.

Bismuth drugs tackle Porphyromonas gingivalis and attune cytokine response in human cells.

Periodontitis is the leading cause of severe tooth loss and edentulism in adults worldwide and is closely linked to systemic conditions such as diabetes and cardiovascular disease. Porphyromonas gingivalis is the key pathogen in periodontitis. Herein, we provided the first evidence that bismuth drugs suppress P.

Green Fluorescent Probe for Imaging His-Tagged Proteins Inside Living Cells.

Small molecule-based fluorescent probes offer great opportunities for specifically tracking proteins in living systems with minimal perturbation on the protein function and localization. Herein, we report a small green fluorescent probe (Ni- NTA-AF) consisting of a Ni-NTA moiety, a fluorescein, and an arylazide group, that binds specifically to His-tagged proteins with fluorescence enhancement in vitro upon photoactivation of the arylazide group. Importantly, the probe can cross the cell membranes and stoichiometrically label His-tagged proteins rapidly (∼15 min) in living prokaryotic and eukaryotic cells exemplified by a DNA repair protein Xeroderma pigmentosum group A (XPA).

Integrative approach for the analysis of the proteome-wide response to bismuth drugs in .

Bismuth drugs, despite being clinically used for decades, surprisingly remain in use and effective for the treatment of infection, even for resistant strains when co-administrated with antibiotics. However, the molecular mechanisms underlying the clinically sustained susceptibility of to bismuth drugs remain elusive. Herein, we report that integration of in-house metalloproteomics and quantitative proteomics allows comprehensive uncovering of the bismuth-associated proteomes, including 63 bismuth-binding and 119 bismuth-regulated proteins from , with over 60% being annotated with catalytic functions.

Integration of fluorescence imaging with proteomics enables visualization and identification of metallo-proteomes in living cells.

Metalloproteins account for nearly one-third of proteins in proteomes. To date, the identification of metalloproteins relies mainly on protein purification and the subsequent characterization of bound metals, which often leads to losses of metal ions bound weakly and transiently. Herein, we developed a strategy to visualize and subsequently identify endogenous metalloproteins and metal-binding proteins in living cells via integration of fluorescence imaging with proteomics.

A Macrocyclic Ruthenium(III) Complex Inhibits Angiogenesis with Down-Regulation of Vascular Endothelial Growth Factor Receptor-2 and Suppresses Tumor Growth In Vivo.

A macrocyclic ruthenium(III) complex [Ru (N O )Cl ]Cl (Ru-1) is reported as an inhibitor of angiogenesis and an anti-tumor compound. The complex is relatively non-cytotoxic towards endothelial and cancer cell lines in vitro, but specifically inhibited the processes of angiogenic endothelial cell tube formation and cancer cell invasion. Moreover, compared with known anti-cancer ruthenium complexes, Ru-1 is distinct in that it suppressed the expression of vascular endothelial growth factor receptor-2 (VEGFR2), and the associated downstream signaling that is crucial to tumor angiogenesis.

Anticancer Gold(III) Porphyrins Target Mitochondrial Chaperone Hsp60.

Identification of the molecular target(s) of anticancer metal complexes is a formidable challenge since most of them are unstable toward ligand exchange reaction(s) or biological reduction under physiological conditions. Gold(III) meso-tetraphenylporphyrin (gold-1 a) is notable for its high stability in biological milieux and potent in vitro and in vivo anticancer activities. Herein, extensive chemical biology approaches employing photo-affinity labeling, click chemistry, chemical proteomics, cellular thermal shift, saturation-transfer difference NMR, protein fluorescence quenching, and protein chaperone assays were used to provide compelling evidence that heat-shock protein 60 (Hsp60), a mitochondrial chaperone and potential anticancer target, is a direct target of gold-1 a in vitro and in cells.

Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells.

Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown.

Rapid labeling of intracellular His-tagged proteins in living cells.

Small molecule-based fluorescent probes have been used for real-time visualization of live cells and tracking of various cellular events with minimal perturbation on the cells being investigated. Given the wide utility of the (histidine)6-Ni(2+)-nitrilotriacetate (Ni-NTA) system in protein purification, there is significant interest in fluorescent Ni(2+)-NTA-based probes. Unfortunately, previous Ni-NTA-based probes suffer from poor membrane permeability and cannot label intracellular proteins.

Selective interaction of Hpn-like protein with nickel, zinc and bismuth in vitro and in cells by FRET.

Hpn-like (Hpnl) is a unique histidine- and glutamine-rich protein found only in Helicobacter pylori and plays a role on nickel homeostasis. We constructed the fluorescent sensor proteins CYHpnl and CYHpnl_1-48 (C-terminal glutamine-rich region truncated) using enhanced cyan and yellow fluorescent proteins (eCFP and eYFP) as the donor-acceptor pair to monitor the interactions of Hpnl with metal ions and to elucidate the role of conserved Glu-rich sequence in Hpnl by fluorescence resonance energy transfer (FRET). CYHpnl and CYHpnl_1-48 exhibited largest responses towards Ni(II) and Zn(II) over other metals studied and the binding of Bi(III) to CYHpnl was observed in the presence of an excess amount of Bi(III) ions (Kd=115±4.

Nickel translocation between metallochaperones HypA and UreE in Helicobacter pylori.

Incorporation of nickel ions to the active sites of urease and hydrogenase is prerequisite for the appropriate functions of the metalloenzymes. Such a process requires the participation of several accessory proteins. Interestingly, some of them are shared by the two enzymes in their maturation processes.

Structure-oriented bioinformatic approach exploring histidine-rich clusters in proteins.

Spatially clustered histidines are commonly found in protein structures. The versatility of histidine coordination favors transition metal bindings, suggesting that spatially clustered histidines are potentially involved in metal binding and thereby play an important role in protein functions. We have applied a bioinformatic approach to identify and characterize histidine-rich clusters (HrCs) protein candidates with a focus on metal coordination.