Abstract:To investigate the structural characteristics of cpsB, a capsular polysaccharide synthesis protein prepared with the help of Lactiplantibacillus plantarum DMDL 9010, the physical and chemical properties, hydrophilic/hydrophobic properties, transmembrane structure, functional sites, phosphorylation sites, signal peptides, structural domains, conserved functional domains, sequence homology, and spatial structure of cpsB were studied and predicted by bioinformatics. The results showed that the relative molecular weight of cpsB was 2 920, the isoelectric point was 6.86, and the protein contains 191 amino acids. It was a hydrophobic protein with high stability. The transmembrane structure prediction demonstrated that it has no transmembrane structure and it is an intracellular protein. CpsB contains 15 phosphate sites. The amino acid sequence does not contain signal peptides, and the encoded proteins are all endocrine proteins. In conserved functional domain prediction, only one PHP domain was found in the gene, which might be involved in regulating the expression of the exopolysaccharide gene. In the secondary structure of cpsB, α-helix accounts for 51.14%, and there are no β-sheets and β-turn structures. The proportion of tertiary structures in cpsB was similar to that of secondary structures. In this study, the functional mechanisms of cpsB, a capsular polysaccharide synthesis protein produced using Lactiplantibacillus plantarum DMDL 9010, were studied in depth. The findings are important to understand its extracellular polysaccharide biosynthesis through genetic engineering.
