Lectins have a central role in translating glycan-encoded information into bioactivity. They are classified according to the fold of their carbohydrate recognition domain (CRD). This structural unit is proposed to be capable to do (much) more than to interact with cognate glycan(s). As outlined for the proof-of-principle case of the galectin CRD, distinct sequence elements appear capable to extend a CRD’s functionality profile: they can implement molecular switches for activity, conformation and quaternary structure, even establish complementary regions for other types of binding partners, letting the CRD gain an unsuspected multifunctionality. By further testing and validating these suggestions, answers may be provided for major unresolved questions, e.g. why galectins belong to the small set of secreted proteins without a signal sequence. This case study teaches the salient lesson of the possibility for a CRD to consist of various structural elements beyond that binding the sugar. Of potential relevance for public health, the idea of a gene capture from the host as origin of viral adhesins that have a galectin-like fold (incl. coronaviruses such as SARS-CoV-2) may inspire innovative modalities to counter pandemic threats.
Grafting is a technique for cultivating plants that combines the advantages of two different plant species, and it has been used as an agricultural technique since ancient times. The cell wall surrounding the plant cell is an extracellular matrix composed of multiple polysaccharides, the composition of which depends on the plant species. Grafting is thought to occur when the cell walls of two grafted plants are reconstituted at their boundaries, resulting in cell or tissue adhesion. In this article, we will introduce the mechanism of artificial plant grafting and the similarity between grafting in nature and grafting in plants, focusing on the function of digestive enzymes of cellulose, the main component of cell walls.
