{"title":"Chitin recognition by a periplasmic chitooligosaccharide-binding protein from Vibrio cholerae","authors":"Takayuki Ohnuma , Teruki Yoshimoto , Wipa Suginta , Tamo Fukamizo","doi":"10.1016/j.carres.2025.109552","DOIUrl":null,"url":null,"abstract":"<div><div>The mechanism of chitin recognition by a periplasmic chitooligosaccharide-binding protein from Vibrio cholerae (VcCBP) was studied by thermal shift assays and isothermal titration calorimetry using di-N-acetylchitobiose, (GlcNAc)2; mono-N-acetylchitobioses, GlcN-GlcNAc and GlcNAc-GlcN; and fully de-N-acetylated chitobiose, (GlcN)2; as the ligands. As judged from the thermal shifts (ΔTm) of VcCBP upon the addition of individual chitobioses, the binding abilities toward VcCBP appeared to decrease in the order of (GlcNAc)2 > GlcN-GlcNAc > GlcNAc-GlcN ≫ (GlcN)2. Although the de-N-acetylation effect of the reducing end GlcNAc was more significant than that of the non-reducing end, both N-acetyl groups were found to cooperatively contribute to the interaction between VcCBP and (GlcNAc)2. The binding affinity of GlcN-GlcNAc to VcCBP was lower than that of (GlcNAc)2 by only 0.5 kcal·mol-1 of ΔG°; however, the entropy gain (-TΔS°) was enhanced in the former compared with the latter. GlcN-GlcNAc are likely to bind loosely to VcCBP but unlikely to undergo translocation by the VcCBP-mediated transporter system.</div></div>","PeriodicalId":9415,"journal":{"name":"Carbohydrate Research","volume":"554 ","pages":"Article 109552"},"PeriodicalIF":2.4000,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Carbohydrate Research","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008621525001788","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The mechanism of chitin recognition by a periplasmic chitooligosaccharide-binding protein from Vibrio cholerae (VcCBP) was studied by thermal shift assays and isothermal titration calorimetry using di-N-acetylchitobiose, (GlcNAc)2; mono-N-acetylchitobioses, GlcN-GlcNAc and GlcNAc-GlcN; and fully de-N-acetylated chitobiose, (GlcN)2; as the ligands. As judged from the thermal shifts (ΔTm) of VcCBP upon the addition of individual chitobioses, the binding abilities toward VcCBP appeared to decrease in the order of (GlcNAc)2 > GlcN-GlcNAc > GlcNAc-GlcN ≫ (GlcN)2. Although the de-N-acetylation effect of the reducing end GlcNAc was more significant than that of the non-reducing end, both N-acetyl groups were found to cooperatively contribute to the interaction between VcCBP and (GlcNAc)2. The binding affinity of GlcN-GlcNAc to VcCBP was lower than that of (GlcNAc)2 by only 0.5 kcal·mol-1 of ΔG°; however, the entropy gain (-TΔS°) was enhanced in the former compared with the latter. GlcN-GlcNAc are likely to bind loosely to VcCBP but unlikely to undergo translocation by the VcCBP-mediated transporter system.
期刊介绍:
Carbohydrate Research publishes reports of original research in the following areas of carbohydrate science: action of enzymes, analytical chemistry, biochemistry (biosynthesis, degradation, structural and functional biochemistry, conformation, molecular recognition, enzyme mechanisms, carbohydrate-processing enzymes, including glycosidases and glycosyltransferases), chemical synthesis, isolation of natural products, physicochemical studies, reactions and their mechanisms, the study of structures and stereochemistry, and technological aspects.
Papers on polysaccharides should have a "molecular" component; that is a paper on new or modified polysaccharides should include structural information and characterization in addition to the usual studies of rheological properties and the like. A paper on a new, naturally occurring polysaccharide should include structural information, defining monosaccharide components and linkage sequence.
Papers devoted wholly or partly to X-ray crystallographic studies, or to computational aspects (molecular mechanics or molecular orbital calculations, simulations via molecular dynamics), will be considered if they meet certain criteria. For computational papers the requirements are that the methods used be specified in sufficient detail to permit replication of the results, and that the conclusions be shown to have relevance to experimental observations - the authors'' own data or data from the literature. Specific directions for the presentation of X-ray data are given below under Results and "discussion".