The trimeric solution structure and fucose-binding mechanism of the core fucosylation-specific lectin PhoSL.

ABSTRACT: The core ?1-6 fucosylation-specific lectin from a mushroom Pholiota squarrosa (PhoSL) is a potential tool for precise diagnosis of cancers. This lectin consists of only 40 amino acids and can be chemically synthesized. We showed here that a synthesized PhoSL peptide formed a trimer by gel filtration and chemical cross-linking assays, and determined a structure of the PhoSL trimer by NMR. The structure possesses a ?-prism motif with a three-fold rotational symmetry, where three antiparallel ?-sheets are tightly connected by swapping of ?-strands. A triad of Trp residues comprises the structural core, forming NH-? electrostatic interactions among the indole rings. NMR analysis with an excess amount of fucose revealed the structural basis for the molecular recognition. Namely, fucose deeply enters a pocket formed at a junction of ?-sheet edges, with the methyl group placed at the bottom. It forms a number of hydrophobic and hydrogen-bonding interactions with PhoSL residues. In spite of partial similarities to the structures of other functionally related lectins, the arrangement of the antiparallel ?-sheets in the PhoSL trimer is novel as a structural scaffold, and thus defines a novel type of lectin structure.

SUBMITTER: Yamasaki K 

PROVIDER: S-EPMC5958098 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature