Basudev Maity

Use of the confined spaces of apo-ferritin and virus capsids as nanoreactors for catalytic reactions.

Self-assembled protein cages providing nanosized internal spaces which are capable of encapsulating metal ions/complexes, enzymes/proteins have great potential for use as catalytic nanoreactors in efforts to mimic confined cellular environments for synthetic applications. Despite many uses in biomineralization, drug delivery, bio-imaging and so on, applications in catalysis are relatively rare. Because of their restricted size, protein cages are excellent candidates for use as vessels to exert control over reaction kinetics and product selectivity. Virus capsids with larger internal spaces can encapsulate multiple enzymes and can mimic natural enzymatic reactions. The apo-ferritin cage is known to accommodate various metal ions/complexes and suitable for organic transformation reactions in an aqueous medium. This review highlights the importance, prospects and recent significant research on catalytic reactions using the apo-ferritin cage and virus capsids.

Observation of gold sub-nanocluster nucleation within a crystalline protein cage

Protein scaffolds provide unique metal coordination environments that promote biomineralization processes. It is expected that protein scaffolds can be developed to prepare inorganic nanomaterials with important biomedical and material applications. Despite many promising applications, it remains challenging to elucidate the detailed mechanisms of formation of metal nanoparticles in protein environments. In the present work, we describe a crystalline protein cage constructed by crosslinking treatment of a single crystal of apo-ferritin for structural characterization of the formation of sub-nanocluster with reduction reaction. The crystal structure analysis shows the gradual movement of the Au ions towards the centre of the three-fold symmetric channels of the protein cage to form a sub-nanocluster with accompanying significant conformational changes of the amino-acid residues bound to Au ions during the process. These results contribute to our understanding of metal core formation as well as interactions of the metal core with the protein environment.

Photocytotoxic ternary copper(II) complexes of histamine Schiff base and pyridyl ligands

AbstractTernary copper(II) complexes of salicylaldehyde-histamine Schiff base (HL) and pyridyl ligands, viz. [Cu(bpy)(L)](ClO4) (1) and [Cu(dppz)(L)](ClO4) (2), where bpy is 2,2′

Design of Bioinorganic Materials at the Interface of Coordination and Biosupramolecular Chemistry

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Functionalization of protein crystals with metal ions, complexes and nanoparticles

-bipyridine (in 1) and dppz is dipyrido[3,2-a:2′

Photoinduced in Vivo Magnetic Resonance Imaging (MRI) with Rapid CO Release from an MnCO-Protein Needle Composite

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Ferrocene-Promoted Photoactivated DNA Cleavage and Anticancer Activity of Terpyridyl Copper(II) Phenanthroline Complexes

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Photoinduced DNA and Protein Cleavage Activity of Ferrocene-Conjugated Ternary Copper(II) Complexes

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Ferrocene-conjugated copper(II) dipyridophenazine complex as a multifunctional model nuclease showing DNA cleavage in red light

-c]phenazine (in 2), were synthesized, characterized and their DNA binding, photo-activated DNA cleavage activity and photocytotoxicity studied. The 1:1 electrolytic one-electron paramagnetic complexes showed a d-d band near 670 nm in aqueous DMF (1:1 v/v). The crystal structure of complex 1 showed the metal in CuN4O distorted square-pyramidal geometry. Complex 2 intercalatively binds to calf-thymus (ct) DNA with a binding constant (Kb) of ∼10 5 M−1. It exhibited moderate chemical nuclease activity but excellent DNA photocleavage activity in red light of 647 nm forming •OH radicals. It showed remarkable photocytotoxicity in human cervical cancer cells (HeLa) giving IC50 of 1.6 μM in visible light (400-700 nm) with low dark toxicity. The photo-induced cell death is via generation of oxidative stress by reactive oxygen species. Graphical AbstractSchiff base copper(II) complex of dipyridophenazine shows remarkable photocytotoxic effect in HeLa cells in visible light (400-700 nm) with reduced dark toxicity via apoptotic pathway. The complex intercalatively binds to ct-DNA, exhibits moderate chemical nuclease activity but excellent DNA photocleavage activity in red light of 705 nm forming •OH radicals.

Impact of metal on the DNA photocleavage activity and cytotoxicity of ferrocenyl terpyridine 3d metal complexes

Protein assemblies have recently become known as potential molecular scaffolds for applications in materials science and bio-nanotechnology. Efforts to design protein assemblies for construction of protein-based hybrid materials with metal ions, metal complexes, nanomaterials and proteins now represent a growing field with a common aim of providing novel functions and mimicking natural functions. However, the important roles of protein assemblies in coordination and biosupramolecular chemistry have not been systematically investigated and characterized. In this personal account, we focus on our recent progress in rational design of protein assemblies using bioinorganic chemistry for (1) exploration of unnatural reactions, (2) construction of functional protein architectures, and (3) in vivo applications.