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Summary: Phytoproteins have been widely implemented in the food industry benefiting from their good functionalities, vast reserves and relatively low cost. However, phytoproteins frequently experience poor solubility, which limits their applications. In our study, the solubility of soy protein isolate (SPI) treated with pH‐shifting increased over 1.8 times; however, the transglutaminase‐induced gel properties were sacrificed. To solve this problem, walnut protein (WP) was used to co‐assemble with SPI during the treatment. The co‐assembly hybrid protein shows significantly better solubility, meanwhile, maintaining the transglutaminase‐induced gel properties and improving the cohesiveness and resilience properties compared with untreated SPI, which behaved an improved water holding capacity during storage. The detailed mechanisms were investigated with rheological analysis, SEM, textural analysis and Fourier transform infrared spectroscopy (FTIR). Overall, our study provided a promising strategy to develop SPI/WP hybrid composites with high solubility and improved gel properties to extend the application of SPI in the food industry. [ABSTRACT FROM AUTHOR]

Protein lattices that shift the structure and shape anisotropy in response to environmental cues are closely coupled to potential functionality. However, to design and construct shape‐anisotropic protein arrays from the same building blocks in response to different external stimuli remains challenging. Here, by a combination of the multiple, symmetric interaction sites on the outer surface of protein nanocages and the tunable features of phenylalanine‐phenylalanine interactions, a protein engineering approach is reported to construct a variety of superstructures with shape anisotropy, including 3D cubic, 2D hexagonal layered, and 1D rod‐like crystalline protein nanocage arrays by using one single protein building block. Notably, the assembly of these crystalline protein arrays is reversible, which can be tuned by external stimuli (pH and ionic strength). The anisotropic morphologies of the fabricated macroscopic crystals can be correlated with the Å‐to‐nm scale protein arrangement details by crystallographic elucidation. These results enhance the understanding of the freedom offered by an object's symmetry and inter‐object π−π stacking interactions for protein building blocks to assemble into direction‐ and shape‐anisotropic biomaterials. [ABSTRACT FROM AUTHOR]

Establishing artificial photosynthesis systems in a simple but effective manner to mitigate the greenhouse effect and address the energy crisis remains challenging. The combination of photocatalysis technology with bioengineering is an emerging field with great potential to construct such artificial photosynthesis systems, but so far, it has barely been explored in this area. Herein, an artificial photocatalysis platform is constructed with high CO2 conversion and H2O splitting capability by integration of CdS QDs into the intra‐subunit interface of H‐type ferritin (Marsupenaeus japonicus), a natural ferroxidase through protein interface redesign. The crystal structure of the synthesized CdS QDs with engineered ferritin molecules as bio‐templates confirmed the design at an atomic level. Notably, upon absorbing desirable visible light (≈420 nm), such a single CdS‐ferritin hybrid molecule is able to selectively catalyze the reduction of CO2 into HCOOH (≈90%), meanwhile catalyzing the oxidation of H2O into O2 in an aqueous environment. The O2 production rate reached to 180 µmol g−1 h−1, and the HCOOH output hit almost 800 µmol g−1 h−1. This work advances the utilization of the four‐helix bundle structure for crafting artificial photosynthesis systems, facilitating the seamless integration of bioengineering and photocatalysis technology. [ABSTRACT FROM AUTHOR]

Ferritin, a ubiquitous iron storage protein, has a crucial role in innate immunity in arthropods, which have no adaptive immune system. Arthropods are thought to have two types of ferritin molecules: the secreted type and the cytosolic type. Here, we present the first crystal structure of ferritin from crustacean, kuruma prawn (Marsupenaeus japonicus), at 1.16 Å resolution. This shrimp ferritin (MjFer) is the cytosolic type, and its structure shows well‐conserved ferritin fold composed of a 4‐helix bundle that assembles into a cage‐like 24‐mer. The structure of MjFer was more similar to those of human and vertebrate ferritins than to that of the secreted‐type arthropod ferritin from an insect. MjFer possesses both a ferroxidase site and a nucleation site, which are the main characteristics of vertebrate H and L chain ferritins, respectively. The first crystal structure of crustacean ferritin, MjFer, has exceptionally high quality that provides the detailed structural information of metal moving pathway in ferritin. PDB Code(s): 6A4U [ABSTRACT FROM AUTHOR]

Protein assemblies with high symmetry are widely distributed in nature. Most efforts so far have focused on repurposing these protein assemblies, a strategy that is ultimately limited by the structures available. To overcome this limitation, methods for fabricating novel self-assembling proteins have received intensive interest. Herein, by reengineering the key subunit interfaces of native 24-mer protein cage with octahedral symmetry through amino acid residues insertion, we fabricated a 16-mer lenticular nanocage whose structure is unique among all known protein cages. This newly non-native protein can be used for encapsulation of bioactive compounds and exhibits high uptake efficiency by cancer cells. More importantly, the above strategy could be applied to other naturally occurring protein assemblies with high symmetry, leading to the generation of new proteins with unexplored functions. [ABSTRACT FROM AUTHOR]

Summary Vitamin A (VA) is a fat‐soluble compound that is essential for physiological functions including vision, fetal growth, immune response, cell differentiation and proliferation. However, its susceptibility to environmental conditions leading to poor stability limits its application in food. This study investigated the interaction between egg white protein (EWP) and VA by spectroscopy and molecular docking. The results indicated one EWP could bind 16.00 ± 0.89 VA molecules and the binding constant is (2.59 ± 0.71) × 105 m−1. What's more, there was a fluorescence resonance energy transfer between EWP and VA, and the Förster radius is 5.28 nm. In addition, VA enhanced the hydrophobic interactions with the EWP, resulting in protein aggregation, larger average particle size and more uniform particle size distribution. Finally, the combination of VA with EWP could significantly improve the photothermal stability and storage stability of VA. These studies indicate that EWP nanocomplexes can be used as ideal delivery carriers for bioactive substances. [ABSTRACT FROM AUTHOR]