Sensing of Proteins by ICD Response of Iron(II) Clathrochelates Functionalized by Carboxyalkylsulfide Groups

Abstract

Recognition of elements of protein tertiary structure is crucial for biotechnological and biomedical tasks; this makes the development of optical sensors for certain protein surface elements important. Herein, we demonstrated the ability of iron(II) clathrochelates (1–3) functionalized with mono-, di- and hexa-carboxyalkylsulfide to induce selective circular dichroism (CD) response upon binding to globular proteins. Thus, inherently CD-silent clathrochelates revealed selective inducing of CD spectra when binding to human serum albumin (HSA) (1, 2), beta-lactoglobuline (2) and bovine serum albumin (BSA) (3). Hence, functionalization of iron(II) clathrochelates with the carboxyalkylsulfide group appears to be a promising tool for the design of CD-probes sensitive to certain surface elements of proteins tertiary structure. Additionally, interaction of 1–3 with proteins was also studied by isothermal titration calorimetry, protein fluorescence quenching, electrospray ionization mass spectrometry (ESI-MS) and computer simulations. Formation of both 1:1 and 1:2 assemblies of HSA with 1–3 was evidenced by ESI-MS. A protein fluorescence quenching study suggests that 3 binds with both BSA and HSA via the sites close to Trp residues. Molecular docking calculations indicate that for both BSA and HSA, binding of 3 to Site I and to an “additional site” is more favorable energetically than binding to Site II.

Multistep synthesis and X-ray structures of carboxyl-terminated hybrid iron(ii) phthalocyaninatoclathrochelates and their postsynthetic transformation into polytopic carboranyl-containing derivatives

“…Cage metal complexes with encapsulated metal ion(s) (clathrochelates 1 ) are known to be chemically robust coordination compounds possessing unusual chemical, optical and redox properties. 1 a , b They have been earlier proposed as prospective drug candidates, 1 b ,2 optical probes, 3 homo- and heterogeneous catalysts, 4 and single-ion molecular magnets 5 with record magnetic characteristics as well. Moreover, mono- and dinuclear macrobicyclic complexes of this type with terminal donor group(s) were earlier reported to be suitable 3D-metalloligands and rigid cage monomers.…”

Removal of anionic and cationic dyes using porous copolymer networks made from a Sonogashira cross‐coupling reaction of diethynyl iron (II) clathrochelate with various arylamines

“…Metal clathrochelates were first reported 50 years ago as three‐dimensional octahedral organometallic complexes with an encapsulated central metal‐ion, 19–21 which subsequently prompted the synthesis of a myriad of clathrochelate derivatives because they offer several advantages, chiefly, a versatile synthesis from environmental‐friendly synthons, high chemical stability, and cost‐effectiveness 22–27 . Among these complexes, iron(II) clathrochelates were found to be prominent derivatives for applications, as biosensors, catalysts for hydrogen generation, materials for electronic transport, organogels, as well as building blocks to make supramolecular cages and metalorganic frameworks (MOFs) 21,22,27–31 .…”

Protein Binding of Benzofuran Derivatives: A CD Spectroscopic and In Silico Comparative Study of the Effects of 4-Nitrophenyl Functionalized Benzofurans and Benzodifurans on BSA Protein Structure

“…Albumins are proteins with high peptide sequences homology, with bovine and human albumins sharing 76% identity [ 1 ], abundant in the circulatory system of mammals where they contribute significantly to the osmotic blood pressure [ 2 ]. Albumins, and primarily BSA, are typically used as protein models and their binding with molecules proposed for biotechnological applications is investigated very extensively in both academic and industrial research areas [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Structurally, albumins present two domains with at least two high-affinity binding sites, as well as other various low-affinity ones [ 10 ].…”