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We firstly report magnetic metal-organic frameworks for selective enrichment and exclusion of proteins for MALDI-TOF MS analysis. Fe3O4@MIL-100(Fe) nanoparticles were achieved by step-by-step assembly on poly(acrylic acid) modified Fe3O4.

Posttranslational modifications modulate the activities of most eukaryotic proteins and play a critical role in all aspects of cellular life. Understanding functional roles of these modifications requires homogeneously modified proteins that are usually difficult to purify from their natural sources. An emerging powerful tool for synthesis of proteins with defined posttranslational modifications is to genetically encode modified amino acids in living cells and incorporate them directly into proteins during the protein translation process. Using this approach, homogenous proteins with tyrosine sulfation, tyrosine phosphorylation mimics, tyrosine nitration, lysine acetylation, lysine methylation, and ubiquitination have been synthesized in large quantities. In this review, we provide a brief introduction to protein posttranslational modifications and the genetic noncanonical amino acid (NAA) incorporation technique, then discuss successful applications of the genetic NAA incorporation approach to produce proteins with defined modifications, and end with challenges and ongoing methodology developments for synthesis of proteins with other modifications.

The autophagic ubiquitin‐like protein LC3 functions through interactions with LC3‐interaction regions (LIRs) of other autophagy proteins, including autophagy receptors, which stands out as a promising protein–protein interaction (PPI) target for the intervention of autophagy. Post‐translational modifications like acetylation of Lys49 on the LIR‐interacting surface could disrupt the interaction, offering an opportunity to design covalent small molecules interfering with the interface. Through screening covalent compounds, we discovered a small molecule modulator of LC3A/B that covalently modifies LC3A/B protein at Lys49. Activity‐based protein profiling (ABPP) based evaluations reveal that a derivative molecule DC‐LC3in‐D5 exhibits a potent covalent reactivity and selectivity to LC3A/B in HeLa cells. DC‐LC3in‐D5 compromises LC3B lipidation in vitro and in HeLa cells, leading to deficiency in the formation of autophagic structures and autophagic substrate degradation. DC‐LC3in‐D5 could serve as a powerful tool for autophagy research as well as for therapeutic interventions. [ABSTRACT FROM AUTHOR]

The tumor protein p53‐inducible nuclear protein 2 (TP53INP2) has been reported to participate in autophagy by interacting with autophagosome‐localized autophagy‐related protein 8 (Atg8) family proteins, including LC3. Here, we uncover a novel function for TP53INP2 in the autophagic degradation of proteins. We identify the ubiquitin‐interacting motif (UIM) of TP53INP2 that mediates its binding to ubiquitin and ubiquitinated proteins. TP53INP2 lacking the UIM is able to displace autophagic adaptor p62 from LC3, which leads to accumulation of ubiquitinated proteins in cells. Furthermore, overexpression of TP53INP2 lacking the UIM sensitizes cells to chloroquine treatment. Our findings indicate that TP53INP2 may act as a novel autophagic adaptor through recruiting ubquitinated substrates to autophagosomes for degradation. [ABSTRACT FROM AUTHOR]

Graphene aerogel (GA)-supported metal–organic framework (MOF) particles with a three-dimensional (3D) architecture were fabricated for the first time via a facile template-free “sol-cryo” method. The prepared MOFs@graphene hybrid aerogels exhibit a 3D interconnected macroporous framework of graphene sheets with uniform dispersion of MOF particles. We also report the first attempt at using the hybrid aerogels as adsorbents for the solid-phase extraction (SPE) of non-steroidal anti-inflammatory drugs (NSAIDs) and the selective enrichment of proteins. The macroporous skeletons of GA provide both low backpressure and rapid mass transfer in SPE application, thus overcoming the obstacle of high backpressure caused by directly packing submicron or micron sized MOF particles into SPE cartridges. Excellent performances including satisfactory recoveries, high sensitivity and good reproducibility were achieved in the extraction of five NSAIDs. The hybrid aerogels also showed an interesting ability for selective enrichment of ribonuclease A (RNase A) and simultaneous exclusion of cytochrome C (Cyt C) and lysozyme (Lyz), which could be attributed to the electrostatic interactions between proteins and the positively charged coordinatively unsaturated metal sites (CUS) in MIL-101. We believe that this work will promote the application of MOFs in adsorption and separation, and our synthetic strategy could be further extended to develop other graphene-based hybrid aerogels. [ABSTRACT FROM AUTHOR]

High Loading Efficiency and Controlled Release of Bioactive Immunotherapeutic Proteins Using Vaterite Nanoparticles (Part. Keywords: controlled release; layer by layer technology; therapeutic proteins delivery; vaterite EN controlled release layer by layer technology therapeutic proteins delivery vaterite 1 1 1 07/21/21 20210701 NES 210701 In article 2100012, Dähne and co-workers provide a framework for the development of a vaterite-based drug delivery system as a carrier for bioactive protein-based cancer therapeutics. Controlled release, layer by layer technology, therapeutic proteins delivery, vaterite. [Extracted from the article]

Abstract: 2-Amino-8-oxononanoic acid has been genetically incorporated into proteins in Escherichia coli by the use of an evolved pyrrolysyl-tRNA synthetase/pylT pair. The direct usage of the exclusive reactivity of the keto group in this amino acid with hydrazide- and alkoxyamine-bearing compounds to site-specifically label proteins under a mild condition close to physiological pH exhibited a very high efficiency. [Copyright &y& Elsevier]

• Ice structuring protein inhibited the water loss from flesh during cryoprotection. • Ice structuring protein curbed myofibrillar protein aggregation during frozen storage. • Ice structuring protein improved the emulsion stability of myofibrillar protein. • Optimal addition of ice structuring protein for cryoprotection of mirror carp is 2.0. Tracking aggregation behaviour and changes in emulsifying properties of myofibrillar protein from mirror carp (Cyprinus carpio L.) induced by its oxidation during frozen storage under the effect of ice structuring protein were investigated. Solubility, net charge, emulsion properties of the sample without ice structuring protein decreased, meanwhile carbonyl, turbidity, the mean diameter in volume and the mean diameter in surface increased during frozen storage. As ice structuring protein addition increased, water-holding capacity and emulsifying properties of samples showed a trend of first increasing and then decreasing, while the tendency of oxidation and aggregation was opposite. Ice structuring protein of 2.0 (g/L) caused the most significant results (P < 0.05). Carbonyl, solubility and emulsion activity index of samples with 2.0 g/L ice structuring protein were decreased by 10.0%, 14.3% and 34.6% after 180 d, respectively. Results suggested that ice structuring protein could effectively prevent moisture loss from flesh, inhibit myofibrillar protein oxidation, and improve emulsion stability during frozen storage. [ABSTRACT FROM AUTHOR]

Siliceous mesostructured cellular foam (MCF) with highly interconnected porous structure, ultralarge pore size and relatively uniform particle size (3–5 μm) was prepared to achieve the mixed-mode and efficient separation of intact proteins. And molecular sieving effect for the first time played an important role in protein separation using mesoporous silica materials as HPLC stationary phase. The spherical silica particles were synthesized via hydrothermal method and the pore size was easily regulated by adding NH 4 F as well as altering the aging time. After aminopropyl derivatization, the chromatographic performance of functionalized mesoporous silica particles was investigated in comparison with those without modification and commercial NH 2 column, and their mixed-mode retention mechanisms were investigated in detail. The superior separation performance for the retention of proteins was obtained on our home-made column in comparison with commercial NH 2 column. The influences of aminopropyl derivatization and mobile phase composition on the column property were also investigated. Moreover, the home-made column showed similar performance for separation of polar anilines and neutral PAHs with the commercial column, owing to mixed-mode retention mechanisms including p–π stacking, electron interaction, hydrophobic effect, π–π EDA interaction and hydrogen bonding. All these results indicated that the aminopropyl modified MCF would be promising in the mixed-mode and efficient separation of biomolecules in addition with small molecules. [ABSTRACT FROM AUTHOR]