Controlling the mechanism of self-assembly in proteins has emerged as a potent tool for various biomedical applications. Silk fibroin self-assembly consists of gradual conformational transition from random coil to β-sheet structure. In this work we elucidated the intermediate secondary conformation in the presence of Ca(2+) ions during fibroin self-assembly. The interaction of fibroin and calcium ions resulted in a predominantly α-helical intermediate conformation, which was maintained to certain extent even in the final conformation as illustrated by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy. Further, to elucidate the mechanism behind this interaction molecular modeling of the N-terminal region of fibroin with Ca(2+) ions was performed. Negatively charged glutamate and aspartate amino acids play a key role in the electrostatic interaction with positively charged calcium ions. Therefore, insights about modulation of self-assembly mechanism of fibroin could potentially be utilized to develop silk-based biomaterials consisting of the desired secondary conformation.

No abstract

Aggregation of α-synuclein has been implicated in Parkinson's disease (PD). While many compounds are known to inhibit α-synuclein aggregation, dissolution of aggregates into their constituent monomers cannot be readily achieved. In this study, using a range of techniques, we have shown that an optimized cocktail of curcumin and β-cyclodextrin, at appreciably low concentrations, not only inhibited aggregation but also broke up the preformed aggregates almost completely. We propose that these compounds exhibit synergy in their action and thus provide us with the exciting prospect of working toward the development of a suitable drug candidate for prevention and treatment of PD.

Edited by Stuart FergusonKeywords: Macromolecular crowder Glucose and sucrose Excluded volume effect Heme retention BSA Lysozyme Soft interaction a b s t r a c t Myoglobin (Mb) undergoes pronounced heme loss under denaturing conditions wherein the proximal histidine gets protonated. Our data show that macromolecular crowding agents (both synthetic and protein based) can appreciably influence the extent of heme retention in Mb. Interestingly, glucose and sucrose, the monomeric constituents of dextran and ficoll-based crowders were much more effective in preventing heme dissociation of Mb, albeit, at much higher concentrations. The protein crowders BSA and lysozyme show very interesting results with BSA bringing about the maximum heme retention amongst all the crowding agents used while lysozyme induced heme dissociation even in the native state of Mb. The stark difference that these protein crowders exhibit when interacting with the heme protein is a testament to the varied interaction potentials that a test protein might be exposed to in the physiological (crowded) milieu.

No abstract

No abstract

No abstract

Synthesis and structural characterization of four new coordination solids of flufenamic acid (ffa), a nonsteroidal anti‐inflammatory drug molecule with biologically significant cobalt and zinc along with an auxiliary N‐donor ligand (4ap or 2ap) are reported: Co3(ffa)6(4ap)2 1, Zn3(ffa)6(4ap)2 2, Co3(ffa)6(2ap)2 3 and Zn3(ffa)6(2ap)2 4. All the four compounds are molecular solids built of analogous linear, trinuclear metal carboxylates. Crystal packing of all the solids were dominated by weak interactions viz. C−F⋅⋅⋅H−C, C−F⋅⋅⋅F−C and C−H⋅⋅⋅H−C; however the positioning of the amino group in the auxiliary ligand led to a different crystal packing in the two pairs of solids containing the same aminopyridine. Two of the four coordination complexes showed higher binding affinity with bovine serum albumin protein in comparison to free ffa.