meso-Indanyl calix[4]pyrrole receptors

Two new meso-indanyl-substituted calix[4]pyrrole receptors, 2 and 3, have been synthesized. A range of calix[4]pyrrole host-neutral molecule complexes crystallise from solutions of 2 in a variety of solvents and the structures of four have been elucidated by X-ray crystallography. The F⁻ and Cl⁻ anion affinities of 2 have been measured in acetonitrile, and are significantly different from the corresponding affinities of the prototypical calix[4]pyrrole, the octamethyl-derivative, 1. ESI-FTICR-MS has been used to determine the relative F⁻ and Cl⁻ anion affinities of receptors 1 and 2 in methanol-acetonitrile solution. Deprotonation of 1 and 2 by fluoride is observed (under the conditions of the MS experiment).     

Electroaddressable Selective Functionalization of Electrode Arrays: Catalytic NADH Detection Using Aryl Diazonium Modified Gold Electrodes

We report the application of 4‐nitrophenyl diazonium modified electrodes towards the electrochemical detection of NADH. Selective activation of individual electrodes on a 5 element array by electro‐addressable conversion of nitro groups to amines and subsequent EDC/NHS crosslinking to the NADH oxidant, pyrroloquinoline quinone (PQQ), is demonstrated. Inactivated electrodes retained nitro functionality and were protected against non‐specific adsorption and mild chemical reactions. Electrodeposition conditions were used to control nitrophenyl film thickness and showed that while increased film thickness leads to greater functionalization density of PQQ, it also results in decreased electron transfer kinetics. The electrodeposition protocol can therefore serve as a method to control electrode functionalization density and film electron transfer kinetics. We believe this simple technique for selective electrode functionalization may facilitate the development of next generation multianalyte electrochemical sensors.     

Low-molecular-weight human serum proteome using ultrafiltration, isoelectric focusing, and mass spectrometry

Identification of the serum proteome is a daunting analytical task due to the complex nature of the sample which has an extremely large dynamic range of protein components. This report addresses this issue by using centrifugal ultrafiltration to enrich the low-molecular-weight (LMW) serum proteome while decreasing the amount of abundant high-molecular-weight proteins. Reduction of the complex nature of the sample was achieved by fractionation of the LMW serum proteins using solution-phase isoelectric focusing (IEF). Multiple enzyme digestions are performed and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analysis of the tandem mass spectra resulted in the identification of 262 proteins belonging to LMW serum proteome. Our results demonstrate the effectiveness of this methodology to isolate and identify LMW proteins with improved confidence in the MS data acquired. In addition, our methodology can be combined with other multidimensional chromatography techniques performed on the peptide level to increase the number of identified proteins.     

Recent advances in the use of ionic liquids as solvents for protein-based materials and chemistry

Proteins are a diverse class of molecules that can act as catalysts and structural components. Interest in their interactions with ionic solvents is on the increase due to the tuneable possibilities for non-aqueous biocatalysis, improved thermostability of biomaterials, and possible roles in medicine, such as drug delivery and use as cell-growth scaffolds. We summarise here the recent examples of these exciting new aspects of protein-ionic solvent interactions, highlighting future directions.     

Terrein

The fungal metabolite terrein (alternative name: trans‐2,3‐di­hydroxy‐4‐propenyl­cyclo­pent‐4‐enone), C₈H₁₀O₃, forms monoclinic (P2₁) crystals. The mol­ecules form hydrogen‐bonded chains, with O?O distances of 2.7115 (16) and 2.8155 (15) Å.