A Mini-Lectin Recognizes N-Glycans with α1,6 linked Fucose
The mini fungal lectin PhoSL was recombinantly produced and characterized. Despitealengthofonly40amino acids, PhoSL exclusively recognizes N-glycans with a1,6linked fucose.C ore fucosylation influences the intrinsic properties and bioactivities of mammalian N-glycoproteins and its level is linked to various cancers. Thus, PhoSLserves as a promising tool for glyco-profiling. Without structural precedence, the crystal structure was solved using the zinc anomalous signal and revealed an interlaced trimer creating a novel protein fold termed β-prism III.
Three biantennary core fucosylated N-glycan azides of 8 to 12 sugars were co-crystallized with PhoSL.The resulting highly resolved structures gave a detailed view on how the exclusive recognition of α1,6 fucosylated N-glycans by such a small protein occurs. This work also provides a protein consensus motif for the observed specificity as well as a glimpse into N-glycan flexibility upon binding.