Speciation and structural transformation of a V-malate complex in the absence and in the presence of a protein: from a dinuclear species to decavanadate.

A strategy for the development of new vanadium-based drugs is the preparation of complexes that target proteins and bear molecules involved in the cellular metabolism as ligands, like α-hydroxycarboxylic acids. Based on these premises, this study explores the solution behaviour of the dioxidovanadium(V) complex of malic acid, Cs[V O(mal)]·2HO, and its interaction with the model protein lysozyme (HEWL) at room and at physiological temperature using V nuclear magnetic resonance (NMR), electrospray ionisation-mass spectrometry (ESI-MS) and X-ray crystallography. The results show the coexistence in aqueous solution of various molecular species containing two or ten V centres.

Dirhodium Tetraacetate Binding to Lysozyme at Body Temperature.

Paddlewheel dirhodium complexes are cytotoxic compounds that are also used as catalysts and in the formation of Rh-based artificial metalloenzymes. Low-temperature structures of adducts formed by the model protein hen egg white lysozyme (HEWL) with dirhodium tetraacetate ([Rh(μ-OCCH)]) when crystals of the protein were treated with the metal compound at 20 °C demonstrated that [Rh(μ-OCCH)] in part breaks down upon reaction with HEWL; dimeric Rh-Rh units bind the side chains of Asp18 and the C-terminal carboxylate, and monometallic fragments coordinate the side chains of Arg14 and His15 in 20% ethylene glycol, 0.100 M sodium acetate at pH 4.

From conventional therapy to novel nano-based approaches. A focus on prostate cancer.

The currently available clinical anticancer approaches pertaining to the treatment of prostate cancer are summarized here. After providing an overview of the main features of this highly impactful global disease, the currently available clinical treatments are briefly reviewed. Then, alternative and innovative nano-based therapeutic options that have been proposed or are currently being explored to significantly improve prostate cancer management (i.

Cytotoxicity and Binding to DNA, Lysozyme, Ribonuclease A, and Human Serum Albumin of the Diiodido Analog of Picoplatin.

Here we investigated cytotoxicity and DNA and protein binding of an iodido analog of picoplatin, the -ammine-diiodido(2-methylpyridine)platinum(II) complex (I-picoplatin). I-picoplatin (IC = 3.7-12.

Formation of Mixed-Valence Cage-Like Polyoxidovanadates at 37°C Upon Reaction of VO(acetylacetonato) With Lysozyme.

Crystals of the model protein lysozyme were grown and soaked with the potential drug VO(acetylacetonato) at 37°C. X-ray diffraction and electron paramagnetic resonance (EPR) data collected at this temperature reveal that mixed-valence cage-like polyoxidovanadate clusters are formed and covalently bind protein residue side chains at physiological temperature.

Cisplatin/Apo-Transferrin Adduct: X-ray Structure and Binding to the Transferrin Receptor 1.

Here, we report the X-ray structure of the adduct formed upon reaction of cisplatin, one of the most prescribed anticancer agents for the clinic treatment of solid tumors, with the apo-form of human serum transferrin (hTF). Two Pt binding sites were identified in both molecules of the adduct present in the crystal asymmetric unit: Pt binds close to the side chains of Met256 and Met499 at the N- and C-lobe, respectively. In the crystal structure, the cisplatin moiety bound to Met256 also interacts with Ser616 from a symmetry related molecule.

Interaction of VO-hydrazonates with lysozyme.

Vanadium compounds (VCs) exhibit a broad range of pharmacological properties, with their most significant medical applications being in the treatment of cancer and diabetes. The therapeutic effects and mode of action of VCs may be associated with their ability to bind proteins and, consequently, understanding the VC-protein interaction is of paramount importance. Among the promising VCs, the VO complex with the aroylhydrazone furan-2-carboxylic acid ((3-ethoxy-2-hydroxybenzylidene)hydrazide, hereafter denoted as VC1), deserves attention, since it exhibits cytotoxicity against various cancer cell lines, including HeLa.

Deciphering the role of neutral diruthenium complexes in protein binding.

The charge of paddlewheel diruthenium complexes has a major role in defining their interaction with proteins: negatively charged complexes bind proteins non-covalently, while cationic complexes form adducts where the Ru core binds to Asp side chains at the equatorial sites, or to the main chain carbonyl groups or the side chains of His, Arg or Lys residues at the axial sites. Here we study the interactions of the neutral compound [Ru(D-p-FPhF)(OCCH)(OCO)]·3HO (D-p-FPhF = N,N'-bis(4-fluorophenyl)formamidinate), a very rare example of a paddlewheel diruthenium compound with three different equatorial ligands, with the model protein bovine pancreatic ribonuclease (RNase A) by means of UV-visible absorption spectroscopy, circular dichroism (CD), electrospray ionization mass spectrometry (ESI-MS) and X-ray crystallography. It is the first attempt to investigate the binding of a neutral diruthenium compound to a protein.

Bioactive Molecules Delivery through Ferritin Nanoparticles: Sum Up of Current Loading Methods.

Ferritin (Ft) is a protein with a peculiar three-dimensional architecture. It is characterized by a hollow cage structure and is responsible for iron storage and detoxification in almost all living organisms. It has attracted the interest of the scientific community thanks to its appealing features, such as its nano size, thermal and pH stability, ease of functionalization, and low cost for large-scale production.

Protein-Protein Stabilization in VO/8-Hydroxyquinoline-Lysozyme Adducts.

The binding of the potential drug [VO(8-HQ)], where 8-HQ is 8-hydroxyquinolinato, with hen egg white lysozyme (HEWL) was evaluated through spectroscopic (electron paramagnetic resonance, EPR, and UV-visible), spectrometric (electrospray ionization-mass spectrometry, ESI-MS), crystallographic (X-ray diffraction, XRD), and computational (DFT and docking) studies. ESI-MS indicates the interaction of [VO(8-HQ)(HO)] and [VO(8-HQ)(HO)] species with HEWL. Room temperature EPR spectra suggest both covalent and non-covalent binding of the two different V-containing fragments.

Non-Covalent and Covalent Binding of New Mixed-Valence Cage-like Polyoxidovanadate Clusters to Lysozyme.

The high-resolution X-ray structures of the model protein lysozyme in the presence of the potential drug [VO(acetylacetonato)] from crystals grown in 1.1 M NaCl, 0.1 M sodium acetate at pH 4.

Picoplatin binding to proteins: X-ray structures and mass spectrometry data on the adducts with lysozyme and ribonuclease A.

The reactivity of the anticancer drug picoplatin (-amminedichlorido(2-methylpyridine)platinum(II) complex) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) was investigated by electrospray ionisation mass spectrometry (ESI MS) and X-ray crystallography. The data were compared with those previously obtained for the adducts of these proteins with cisplatin, carboplatin and oxaliplatin under the same experimental conditions. ESI-MS data show binding of Pt to both proteins, with fragments retaining the 2-methylpyridine ligand and, possibly, a chloride ion.

Structural insights and aggregation propensity of a super-stable monellin mutant: A new potential building block for protein-based nanostructured materials.

Protein fibrillation is commonly associated with pathologic amyloidosis. However, under appropriate conditions several proteins form fibrillar structures in vitro that can be used for biotechnological applications. MNEI and its variants, firstly designed as single chain derivatives of the sweet protein monellin, are also useful models for protein fibrillary aggregation studies.

On the mechanism of action of arsenoplatins: arsenoplatin-1 binding to a B-DNA dodecamer.

The reaction of Pt-based anticancer agents with arsenic trioxide affords robust complexes known as arsenoplatins. The prototype of this family of anticancer compounds is arsenoplatin-1 (AP-1) that contains an As(OH) fragment linked to a Pt(II) moiety derived from cisplatin. Crystallographic and spectrometric studies of AP-1 binding to a B-DNA double helix dodecamer are presented here, in comparison with cisplatin and transplatin.

A Diruthenium Metallodrug as a Potent Inhibitor of Amyloid-β Aggregation: Synergism of Mechanisms of Action.

The physical and chemical properties of paddlewheel diruthenium compounds are highly dependent on the nature of the ligands surrounding the bimetallic core. Herein, we compare the ability of two diruthenium compounds, [RuCl(D--FPhF)(OCCH)]·HO () (D--FPhF = -bis(4-fluorophenyl)formamidinate) and K[Ru(OCO)]·3HO (), to act as inhibitors of amyloid aggregation of the Aβ peptide and its peculiar fragments, Aβ and Aβ. A wide range of biophysical techniques has been used to determine the inhibition capacity against aggregation and the possible mechanism of action of these compounds (Thioflavin T fluorescence and autofluorescence assays, UV-vis absorption spectroscopy, circular dichroism, nuclear magnetic resonance, mass spectrometry, and electron scanning microscopy).

Stabilization and Binding of [V O ] and Unprecedented [V O (NO )] to Lysozyme upon Loss of Ligands and Oxidation of the Potential Drug V O(acetylacetonato).

High-resolution crystal structures of lysozyme in the presence of the potential drug V O(acetylacetonato) under two different experimental conditions have been solved. The crystallographic study reveals the loss of the ligands, the oxidation of V to V and the subsequent formation of adducts of the protein with two different polyoxidovanadates: [V O ] , which interacts with lysozyme non-covalently, and the unprecedented [V O (NO )] , which is covalenty bound to the side chain of an aspartate residue of symmetry related molecules.

Steric hindrance and charge influence on the cytotoxic activity and protein binding properties of diruthenium complexes.

Paddlewheel diruthenium complexes are being used as metal-based drugs. It has been proposed that their charge and steric properties determine their selectivity towards proteins. Here, we explore these parameters using the first water-soluble diruthenium complex bearing two formamidinate ligands, [RuCl(DPhF)(OCCH)], and two derivatives, [RuCl(DPhF)(OCCH)] and K[Ru(DPhF)(CO)] (DPhF = N,N'-diphenylformamidinate), with one formamidinate.

Cisplatin binding to angiogenin protein: new molecular pathways and targets for the drug's anticancer activity.

Cisplatin (CisPt), a platinum-based chemotherapeutic widely used in the treatment of various cancers, has multiple mechanisms of action, including nuclear DNA (nDNA) and mitochondrial DNA (mDNA) damage and cytoskeletal perturbations affecting, in turn, the membrane transporter activity. CisPt binding to proteins and enzymes may modulate its biochemical mechanism of action and is associated with cancer cell resistance to the drug. In this work, we investigate the interaction between cisplatin and angiogenin (Ang), a protein strongly expressed in many types of cancer and a potent angiogenic factor.

Dirhodium tetraacetate binding to a B-DNA double helical dodecamer probed by X-ray crystallography and mass spectrometry.

The reaction of the cytotoxic compound dirhodium tetraacetate with a B-DNA double helical dodecamer was studied by X-ray crystallography and mass spectrometry. The structure of the dirhodium/DNA adduct reveals a dimetallic center binding to an adenine axial coordination. Complementary information has been gained through ESI MS measurements.

Implications of Protein Interaction in the Speciation of Potential VO-Pyridinone Drugs.

Vanadium complexes (VCs) are promising agents for the treatment, among others, of diabetes and cancer. The development of vanadium-based drugs is mainly limited by a scarce knowledge of the active species in the target organs, which is often determined by the interaction of VCs with biological macromolecules like proteins. Here, we have studied the binding of [VO(empp)] (where Hempp is 1-methyl-2-ethyl-3-hydroxy-4(1)-pyridinone), an antidiabetic and anticancer VC, with the model protein hen egg white lysozyme (HEWL) by electrospray ionization-mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR), and X-ray crystallography.

Impact of Hydrophobic Chains in Five-Coordinate Glucoconjugate Pt(II) Anticancer Agents.

This study describes new platinum(II) cationic five-coordinate complexes () of the formula [PtR(NHC)(dmphen)(ethene)]CFSO (dmphen = 2,9-dimethyl-1,10-phenanthroline), containing in their axial positions an alkyl group R (methyl or octyl) and an imidazole-based NHC-carbene ligand with a substituent R' of variable length (methyl or octyl) on one nitrogen atom. The Pt-carbene bond is stable both in DMSO and in aqueous solvents. In DMSO, a gradual substitution of dmphen and ethene is observed, with the formation of a square planar solvated species.

A new and efficient procedure to load bioactive molecules within the human heavy-chain ferritin nanocage.

For their easy and high-yield recombinant production, their high stability in a wide range of physico-chemical conditions and their characteristic hollow structure, ferritins (Fts) are considered useful scaffolds to encapsulate bioactive molecules. Notably, for the absence of immunogenicity and the selective interaction with tumor cells, the nanocages constituted by the heavy chain of the human variant of ferritin (hHFt) are optimal candidates for the delivery of anti-cancer drugs. hHFt nanocages can be disassembled and reassembled to allow the loading of cargo molecules, however the currently available protocols present some relevant drawbacks.

Cisplatin Binding to Human Serum Transferrin: A Crystallographic Study.

The molecular mechanism of how human serum transferrin (hTF) recognizes cisplatin at the atomic level is still unclear. Here, we report the molecular structure of the adduct formed upon the reaction of hTF with cisplatin. Pt binds the side chain of Met256 (at the N-lobe), without altering the protein overall conformation.