Analyzing world city network by graph convolutional networks.

British scholar Peter Taylor constructed the World City Network by analyzing the office networks of multinational companies, enabling a network perspective on world cities. However, this method has long been hindered by data deficiencies and update delays. In this study, we utilized publicly available, real-time updated data on global routes to construct the World City Network, thereby addressing the issues of data insufficiency and delayed updates in the existing model. For the first time, advanced Graph Convolutional Networks were employed to analyze the World City Network, and we introduced GCNRank. Finally, we compared GCNRank with other centrality measures and found that GCNRank provides a more detailed representation of city rankings and effectively avoids local optima.

Mechanistic analysis of thermal stability in a novel thermophilic polygalacturonase MlPG28B derived from the marine fungus Mucor lusitanicus.

In this study, heterologous MlPG28B expression was obtained by cloning the Mucor lusitanicus gene screened from a marine environment. The enzyme activity of MlPG28B was maximum at 60 °C, 30 % of the enzyme activity was retained after incubation at 100 °C for 30 min, and enzyme activity was still present after 60 min incubation, one of the best thermostable polygalacturonases characterized until now. The high-purity oligosaccharide standards (DP2-DP7) were prepared with polygalacturonic acid as a substrate. Kinetic parameters showed that MlPG28B at the optimum temperature has a low Km value (3055 ± 1104 mg/L), indicating high substrate affinity. Sequence alignment analysis inferred key residues Cys276, Cys284, Lys107, and Gln237 for MlPG28B thermal stability. Molecular docking and molecular dynamics simulation results indicated that MlPG28B has flexible T1 and T3 loops conducive to substrate recognition, binding, and catalysis and forms a hydrogen bond to the substrate by a highly conserved residue Asn161 in the active-site cleft. Based on site-directed mutation results, the five residues are key in determining MlPG28B thermal stability. Therefore, MlPG28B is a promising candidate for industrial enzymes in feed preparation.

Recent advances in polygalacturonase: Industrial applications and challenges.

This review focuses on the applications of polygalacturonase (PG), one of the most commercially produced enzymes on the biocatalyst market, in the food, beverage, feed, textile, and paper industries. Most PGs are acidic mesophilic enzymes, as shown by a summary of their biochemical properties. However, the acidic PGs discovered to date are insufficiently effective for industrial applications. The sequence and structural characteristics of thermophilic PGs are analyzed based on the results of extensive discussions regarding the catalytic mechanism and structural characteristics of PGs with shared right-handed parallel ß-helical structures. In addition, the molecular modification methods for obtaining thermostable PGs are systematically presented. Notably, the demand for alkaline heat-resistant PGs has increased significantly concurrent with the biomanufacturing industry development. Therefore, this review also provides a theoretical guideline for mining heat-resistant PG gene resources and modifying PG thermostability.