AUTHOR=Kock Michael , Brückner Stefan , Wozniak Nina , Maestre-Reyna Manuel , Veelders Maik , Schlereth Julia , Mösch Hans-Ulrich , Essen Lars-Oliver 

TITLE=Structural and Functional Characterization of PA14/Flo5-Like Adhesins From Komagataella pastoris

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02581

DOI=10.3389/fmicb.2018.02581

ISSN=1664-302X

ABSTRACT=<p>Cell–cell and cell-substrate based adhesion of yeasts are major determinants of their adoption of different life styles. Genome-mining of ascomycetous GPI-anchored cell wall proteins with lectin-like PA14 domains identified a unique class of putative adhesins in the clade of methylotrophic <italic>Komagataella</italic> yeasts, many of which are known to colonize plants and insects involving yet unknown adhesion mechanisms. Here, we report the functional and structural analysis of two of its members: <italic>Kp</italic>Flo1 (=Cea1), that is highly specific for terminal <italic>N</italic>-acetylglucosamine moieties, and <italic>Kp</italic>Flo2, which represents an orphan lectin with intact binding site but unknown specificity. Crystal structures of the Cea1 adhesion domain complexed to <italic>N</italic>-acetylglucosamine and <italic>N</italic>,<italic>N</italic>′-diacetylchitobiose reveal a Ca<sup>2+</sup>-dependent binding mode that differs from other members of the PA14/Flo5 adhesin family. Heterologous expression of Cea1A in <italic>Saccharomyces cerevisiae</italic> promotes cellular adhesion to non-reducing ends of non-crystalline chitin. Overall, our data suggest that high-affinity recognition of β-GlcNAc-capped glycans by Cea1 enable <italic>Komagataella</italic> species to interact with surface cues present in fungi and insects.</p>