Are vanadium complexes druggable against the main protease Mpro of SARS-CoV-2? - A computational approach

In silico techniques helped explore the binding capacities of the SARS-CoV-2 main protease (M^pro) for a series of metalloorganic compounds. Along with small size vanadium complexes a vanadium-containing derivative of the peptide-like inhibitor N3 (N-[(5-methylisoxazol-3-yl)carbonyl]alanyl-l-valyl-N1-((1R,2Z)-4-(benzyloxy)-4-oxo-1-{[(3R)-2-oxopyrrolidin-3-yl] methyl }but-2-enyl)-l-leucinamide) was designed from the crystal structure with PDB entry code 6LU7. On theoretical grounds our consensus docking studies evaluated the binding affinities at the hitherto known binding site of Chymotrypsin-like protease (3CLpro) of SARS-CoV-2 for existing and designed vanadium complexes. This main virus protease (M^pro) has a Cys-His dyad at the catalytic site that is characteristic of metal-dependent or metal-inhibited hydrolases. M^pro was compared to the human protein-tyrosine phosphatase 1B (hPTP1B) with a comparable catalytic dyad. HPTP1B is a key regulator at an early stage in the signalling cascade of the insulin hormone for glucose uptake into cells. The vanadium-ligand binding site of hPTP1B is located in a larger groove on the surface of M^pro. Vanadium constitutes a well-known phosphate analogue. Hence, its study offers possibilities to design promising vanadium-containing binders to SARS-CoV-2. Given the favourable physicochemical properties of vanadium nuclei, such organic vanadium complexes could become drugs not only for pharmacotherapy but also diagnostic tools for early infection detection in patients. This work presents the in silico design of a potential lead vanadium compound. It was tested along with 20 other vanadium-containing complexes from the literature in a virtual screening test by docking to inhibit M^pro of SARS-CoV-2.

Used battery collection in central Mexico: metal content, legislative/management situation and statistical analysis

A statistical analysis of a used battery collection campaign in the state of Tlaxcala, Mexico, is presented. This included a study of the metal composition of spent batteries from formal and informal markets, and a critical discussion about the management of spent batteries in Mexico with respect to legislation. A six-month collection campaign was statistically analyzed: 77% of the battery types were "AA" and 30% of the batteries were from the informal market. A substantial percentage (36%) of batteries had residual voltage in the range 1.2-1.4 V, and 70% had more than 1.0 V; this may reflect underutilization. Metal content analysis and recovery experiments were performed with the five formal and four more frequent informal trademarks. The analysis of Hg, Cd and Pb showed there is no significant difference in content between formal and informal commercialized batteries. All of the analyzed trademarks were under the permissible limit levels of the proposed Mexican Official Norm (NOM) NMX-AA-104-SCFI-2006 and would be classified as not dangerous residues (can be thrown to the domestic rubbish); however, compared with the EU directive 2006/66/EC, 8 out of 9 of the selected battery trademarks would be rejected, since the Mexican Norm content limit is 20, 7.5 and 5 fold higher in Hg, Cd and Pb, respectively, than the EU directive. These results outline the necessity for better regulatory criteria in the proposed Mexican NOM in order to minimize the impact on human health and the environment of this type of residues.