Structural basis for specific recognition of core fucosylation in N-glycans by Pholiota squarrosa lectin (PhoSL).

Fucosylation of the N-glycan core via the α1-6 linkage (core fucosylation) is detected in specific types of cancers and related diseases, and thereby serves for a relevant biomarker. The lectin from a mushroom Pholiota squarrosa (PhoSL) shows a clear specificity to core fucosylation, without recognizing those with other types of fucosylation, such as the H type via the α1-2 linkage or the Lewis type via the α1-3 or α1-4 linkage. Here we determined the crystal structure of the PhoSL trimer in complex with a disaccharide fucose(α1-6)N-acetylglucosamine (GlcNAc).

Is it possible for short peptide composed of positively- and negatively-charged "hydrophilic" amino acid residue-clusters to form metastable "hydrophobic" packing?

We theoretically and experimentally analyzed a conformational ensemble of a small, characteristic polypeptide consisting of positively- and negatively-charged amino acid residue clusters, (Lys)9(Glu)9(Lys)9, designed based on the supercoiled DNA-recognition (SDR) domain, with the capability of preferentially binding to supercoiled DNA. Advanced molecular dynamics (MD) simulations coupled with a generalized ensemble technique revealed that substantial amounts of ordered, helical structures were present at the boundaries of the Lys and Glu segments in the obtained conformational ensemble. In fact, the helical content of the peptide calculated from our MD simulations was consistent with that estimated from our experimental analysis employing circular dichroism (CD) spectroscopy.