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Conserved tryptophan residues are critical for the structure and the stability of β/γ‐crystallin in the lenses of vertebrates. During aging, in which the lenses are continuously exposed to ultraviolet irradiation and other environmental stresses, oxidation of tryptophan residues in β/γ‐crystallin is triggered and impacts the lens proteins to varying degrees. Kynurenine derivatives, formed by oxidation of tryptophan, accumulate, resulting in destabilization and insolubilization of β/γ‐crystallin, which correlates with age‐related cataract formation. To understand the contribution of tryptophan modification on the structure and stability of human βB2‐crystallin, five tryptophan residues were mutated to phenylalanine considering its similarity in structure and hydrophilicity to kynurenine. Among all mutants, W59F and W151F altered the stability and homo‐oligomerization of βB2‐crystallin—W59F promoted tetramerization whereas W151F blocked oligomerization. Most W59F dimers transformed into tetramer in a month, and the separated dimer and tetramer of W59F demonstrated different structures and hydrophobicity, implying that the biochemical properties of βB2‐crystallin vary over time. By using SAXS, we found that the dimer of βB2‐crystallin in solution resembled the lattice βB1‐crystallin dimer (face‐en‐face), whereas the tetramer of βB2‐crystallin in solution resembled its lattice tetramer (domain‐swapped). Our results suggest that homo‐oligomerization of βB2‐crystallin includes potential inter‐subunit reactions, such as dissociation, unfolding, and re‐formation of the dimers into a tetramer in solution. The W>F mutants are useful in studying different folding states of βB2‐crystallin in lens. [ABSTRACT FROM AUTHOR]

Vitamin Ks are expected to contribute bone and cardiovascular health. Especially, menaquinone-7 has a higher bioavailability and a longer half-life than other vitamin Ks in the human body. However, their low water-solubility limits their application. On the other hand, Bacillus subtilis natto produces a water-soluble complex, which comprises menaquinone-7 and peptides. The peptide named K-binding factor (KBF) has been reported as the main component of the complex. In the present, the structural characteristics of KBF were studied. Mass spectrometry showed significant peaks at m / z  = 1050, while the previous PAGE suggested that molecular weight of KBF was ~ 3k. Amino acid analysis revealed that the 1k peptides were the various combinations of nine amino acids, among which Asx, Glx, Val, Leu and Met were found to be the most abundant. The peptides could serve as detergent properties. The 1k peptides could be isolated by reverse-phase high performance liquid chromatography. The bundle of three 1k detergent-like peptides would participate to the micelle structure containing menqauinone-7 inside. In conclusion, a basic unit of KBF would be the ~ 1k peptides, and the three basic unit assemble to the ~ 3k bundle, then the bundle form a water-soluble micelle including menqauinone-7 inside. [ABSTRACT FROM AUTHOR]

Background and Objectives Neighborhood places that facilitate older residents to meet and interact (third places) receive an increasing research interest as studies have consistently shown the benefits of social engagement for older adults' health. This scoping review synthesized the findings of studies examining the role of third places in older adults' social engagement. Research Design and Methods Searching 5 databases (CINAHL, Medline, PsycInfo, Scopus, and Web of Science) in October 2021, this study identified quantitative and qualitative studies that examined the relationships between third places and social engagement (interaction and network) among older adults. Results A total of 32 studies (12 quantitative and 20 qualitative studies) met the eligibility criteria. These studies examined 4 types of third place, namely, community facilities, local businesses, open/green spaces, and transition spaces. More than two thirds of the studies reviewed found that access to community facilities, local businesses, and open/green spaces were related to older adults' social interaction. For the relationships between third places and social networks, the importance of accessible local businesses and the quality of open/green spaces was supported by fewer studies. Discussion and Implications The findings of quantitative and qualitative studies suggest that local places that are convenient to visit and comfortable to stay in for older adults are likely to enhance their social interaction and network. However, more specific evidence is needed to inform the planning and design of third places. The review discusses future research topics that address the gaps identified in the current literature. [ABSTRACT FROM AUTHOR]

Three domain fragments of a multi‐domain protein, ER‐60, were ligated in two short linker regions using asparaginyl endopeptidase not involving denaturation. To identify appropriate ligation sites, by selecting several potential ligation sites with fewer mutations around two short linker regions, their ligation efficiencies and the functions of the ligated ER‐60s were examined experimentally. To evaluate the dependence of ligation efficiencies on the ligation sites computationally, steric hinderances around the sites for the ligation were calculated through molecular dynamics simulations. Utilizing the steric hindrance, a site‐dependent ligation potential index was introduced as reproducing the experimental ligation efficiency. Referring to this index, the reconstruction of ER‐60 was succeeded by the ligation of the three domains for the first time. In addition, the new ligation potential index well‐worked for application to other domain ligations. Therefore, the index may serve as a more time‐effective tool for multi‐site ligations. [ABSTRACT FROM AUTHOR]