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In this study, the effect of ultrasonic, heating, and enzymatic treatments on the structural and emulsifying attributes of walnut protein isolate (WNPI) was assessed and compared. Ultrasonic, heating, and enzymatic treatments all effectively improved WNPI's emulsifying capacity and stability, especially ultrasonication. Ultrasonication (400 W, 30 min) obviously made WNPI's structure looser and more unfolded, in turn led to 1.57-fold and 2.67-fold increase in EAI and ESI of WNPI, respectively. Besides, the exposure of WNPI′ hydrophobic groups induced by sonication, reflected in a 3.64-fold increase in WNPI's surface hydrophobicity, may also contributes to the increase of WNPI's emulsifying properties. Furthermore, the emulsion stabilized by UT-WNPI exhibited the best lipid and protein oxidative stabilities during storage at 55 °C for 7 days. Compared to emulsion stabilized by the untreated WNPI, hydroperoxide, TBARS, and protein carbonyl contents in the emulsion stabilized by UT-WNPI decreased by 46.92%, 40.74%, and 33.89%, respectively. Our results clarify ultrasonication is the best for improving the emulsifying properties of walnut protein, thereby broadening walnut protein's application in the emulsified food. [Display omitted] • Developing walnut protein as a potential emulsifier in the food industry. • The sonicated walnut protein exhibited the best emulsifying properties. • The sonicated walnut protein stabilized emulsion had the best oxidative stability. • The sonication converted walnut protein's α-helix into random coil. • The sonication improved walnut protein's surface hydrophobicity. [ABSTRACT FROM AUTHOR]

Abstract: GNA1946, a conserved outer membrane lipoprotein from Neisseria meningitidis, has been identified as a candidate antigen for an urgently needed broad-spectrum meningococcal vaccine. It has been predicted to be a periplasmic receptor in the d-methionine uptake ABC transporter system. The crystal structure of GNA1946 was solved by the single-wavelength anomalous dispersion (SAD) method to a resolution of 2.25Å, and it reveals a Venus flytrap-like structure. GNA1946 consists of two globular lobes connected by a hinge region. Surprisingly, the structure showed an l-methionine bound within the cleft between the lobes. A comparison of GNA1946 with two other outer membrane lipoproteins, the l-methionine-binding Tp32 from Treponema pallidum and the dipeptide GlyMet-binding protein Pg110 from Staphylococcus aureus, revealed that although these three proteins share low sequence similarities, there is a high degree of structural conservation and similar substrate-binding frameworks. Our results reveal that GNA1946 is an l-methionine binding lipoprotein in the outer membrane, and should function as an initial receptor for ABC transporters with high affinity and specificity. The GNA1946 structure reported here should provide a valuable starting point for the development of a broad-spectrum meningococcal vaccine. [Copyright &y& Elsevier]

Dewatering is the first step in the subsequent treatment and disposal of food waste digestate (FWD). However, FWD is difficult to dewatering. In this study, persulfate was synergistic oxidized by ozone to improve digestate dewaterability. The optimal conditions was at pH = 3, O 3 ＝40 mg/g TS and PDS＝0.1 g/g TS, under which the reductions in the normalized capillary suction time (NCST) and bound moisture (BM) of the FWD were 89.97% and 65.79%, respectively. Hydrophilic functional groups (oxygen- and nitrogen-containing groups) and hydrophilic protein molecular structures were decomposed by the reactive species of sulfate radical (SO 4 ·-) and hydroxyl radicals (·OH) generated in the ozone-persulfate oxidation process, disrupting the binding between EPS and water molecules. The contributions of SO 4 ·- and ·OH to digestate dewaterability were 42.51% and 28.55%. In addition, the introduction of H+ reduced electrostatic repulsion and contributed to the condensation of digestate flocs. The environmental implication assessment and economic analysis suggested that the O 3 /PDS oxidation process was cost-effective and has a low environmental implication when applied to the FWD dewaterability improvement process. These results can serve as a reference for the management of FWD and further improvement of FWD treatment and disposal efficiency. [Display omitted] • Ozone was effective in PDS activation for digestate dewaterability improvement. • Protein in ECPS were effectively decomposed at the presence of active radicals. • SO 4 ·- was the dominated radical species in ozone-persulfate oxidation process. • Acidic conditions can accelerate the formation of SO 4 ·-. [ABSTRACT FROM AUTHOR]

Abstract: Protoporphyrinogen IX oxidase (PPO) converts protoporphyrinogen IX to protoporphyrin IX, playing an important part in the heme/chlorophyll biosynthetic pathway. Bacillus subtilis PPO (bsPPO) is unique among PPO family members in that it is a soluble monomer, is inefficiently inhibited by the herbicide acifluorfen (AF) and has broader substrate specificity than other PPO enzymes. Here, we present the crystal structure of bsPPO bound to AF. Our structure shows that the AF molecule binds to a new site outside the previously identified inhibitor binding pocket. Most importantly, the benzene ring of the 2-nitrobenzoic acid moiety of AF lies parallel to the isoalloxazine ring of FAD at a distance of less than 3.5Å, providing a framework for the interaction of FAD with the substrate protoporphyrinogen IX. Furthermore, our structure reveals that the larger substrate binding chamber and predominantly positively charged chamber surface of bsPPO are more favorable for the binding of coproporphyrinogen-III. These crystallographic findings uncover biochemically unique properties of bsPPO, providing important information for further understanding the enzymatic mechanism. [Copyright &y& Elsevier]