Carbohydrate–protein interactions and their biosensing applications

Abstract

Carbohydrate recognition is clearly present throughout nature, playing a major role in the initial attachment of one biological entity to another. The important question is whether these prevalent interactions could provide a real suitable alternative to the use of antibodies or nucleic acid for detection and identification. Currently, examples of carbohydrates being employed in biological detection systems are limited. The challenges of using carbohydrate recognition for detection mainly come from the weak affinity of carbohydrate-protein interactions, the lack of versatile carbohydrate scaffolds with well-defined structures, and the less developed high-information-content, real-time, and label-free assay technology. In this review, we focus on discussing the characteristics of carbohydrate-protein interactions in nature and the methods for carbohydrate immobilization based on surface coupling chemistry in terms of their general applicability for developing carbohydrate- and lectin-based label-free sensors. Furthermore, examples of innovative design of multivalent carbohydrate-protein interactions for sensor applications are given. We limit our review to show the feasibility of carbohydrate and lectin as recognition elements for label-free sensor development in several representative cases to formulate a flexible platform for their use as recognition elements for real-world biosensor applications.

RapA2 Is a Calcium-binding Lectin Composed of Two Highly Conserved Cadherin-like Domains That Specifically Recognize Rhizobium leguminosarum Acidic Exopolysaccharides

“…It is not surprising that monosaccharide-protein interactions show equilibrium dissociation constants (K D ) in the mM range. However, it has been observed that in the biological context, avidity is increased 100 -10.000-fold due to the multivalency of the interaction (40). Because the RapA2 protein contains no other elements than the two homologous Ra/CHDL domains, it suggests that each domain constitutes a carbohydrate binding module.…”

Flow Lectin Affinity Chromatography−A Model with Sambucus nigra Agglutinin

“…Divalent metals must be present for carbohydrate binding as they are necessary for SNA-I to have the active conformation to interact with the STn antigen [24].…”

Synthesis of 1,2,3-triazole-linked galactohybrids and their inhibitory activities on galectins

“…The axial position of H-C(2) and H-C(3) in both anomeric forms is confirmed by 3 J H2-H3 ~ 11 Hz. Finally, the axial position of HO-C(4) and the equatorial position of H-C(4) in both anomers was proved by 3 The binding affinities of galectin-1 and -3 for selected compounds 17 were estimated by a fluorescent anisotropy assay. 40,41,42 Compounds depicted in Table 3 were tested up to 5 mM concentrations and gave K d values in the range of 1-4 mM, except trisaccharide 17j.…”

“…These include lectin-carbohydrate recognition 1,2,3 and processes catalyzed by glycosidases, 4,5,6 glycosyltransferases 7 and glycogen phosphorylases. 8 Very often modified carbohydrates are used to investigate these processes 9,10 and to create suitable inhibitors of the aforementioned enzymes.…”