Atomic crystal structure and sugar specificity of a beta-trefoil lectin domain from the ectomycorrhizal basidiomycete Laccaria bicolor.
Acebron, I., Campanero-Rhodes, M.A., Solis, D., Menendez, M., Garcia, C., Lillo, M.P., Mancheno, J.M.(2023) Int J Biol Macromol 233: 123507-123507
- PubMed: 36754262 
- DOI: https://doi.org/10.1016/j.ijbiomac.2023.123507
- Primary Citation of Related Structures:  
8B8F, 8B97 - PubMed Abstract: 
Lectins from fruiting bodies are a diverse group of sugar-binding proteins from mushrooms that face the biologically relevant challenge of discriminating self- from non-self carbohydrate structures, therefore providing a basis for an innate defence system. Such a system entails both detection and destruction of invaders and/or feeders, and in contrast to more complex organisms with immense immune systems, these two functions normally rely on multitasking lectins, namely, lectins with different functional modules. Here, we present a novel fungal lectin, LBL, from the basidiomycete Laccaria bicolor. Using a diverse set of biophysical techniques, we unveil the fine details of the sugar-binding specificity of the N-terminal β-trefoil of LBL (LBL 152 ), whose structure has been determined at the highest resolution so far reported for such a fold. LBL 152 binds complex poly-N-Acetyllactosamine polysaccharides and also robust LBL 152 binding to Caenorhabditis elegans and Drosophila melanogaster cellular extracts was detected in microarray assays, with a seeming preference for the fruit fly adult and pupa stages over the larva stage. Prediction of the structure of the C-terminal part of LBL with AlphaFold reveals a tandem repeat of two structurally almost identical domains of around 110 amino acids each, despite sharing low sequence conservation.
Organizational Affiliation: 
Department of Crystallography and Structural Biology, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.