Lectin Domains of Polypeptide GalNAc Transferases Exhibit Glycopeptide Binding Specificity

TY - JOUR

T1 - Lectin Domains of Polypeptide GalNAc Transferases Exhibit Glycopeptide Binding Specificity

AU - Pedersen, Johannes W

AU - Bennett, Eric P

AU - Schjoldager, Katrine T-B G

AU - Meldal, Morten

AU - Holmér, Andreas P

AU - Blixt, Ola

AU - Cló, Emiliano

AU - Levery, Steven B

AU - Clausen, Henrik

AU - Wandall, Hans H

PY - 2011/9/16

Y1 - 2011/9/16

N2 - UDP-GalNAc:polypeptide α-N-acetylgalactosaminyltransferases (GalNAc-Ts) constitute a family of up to 20 transferases that initiate mucin-type O-glycosylation. The transferases are structurally composed of catalytic and lectin domains. Two modes have been identified for the selection of glycosylation sites by GalNAc-Ts: confined sequence recognition by the catalytic domain alone, and concerted recognition of acceptor sites and adjacent GalNAc-glycosylated sites by the catalytic and lectin domains, respectively. Thus far, only the catalytic domain has been shown to have peptide sequence specificity, whereas the primary function of the lectin domain is to increase affinity to previously glycosylated substrates. Whether the lectin domain also has peptide sequence selectivity has remained unclear. Using a glycopeptide array with a library of synthetic and recombinant glycopeptides based on sequences of mucins MUC1, MUC2, MUC4, MUC5AC, MUC6, and MUC7 as well as a random glycopeptide bead library, we examined the binding properties of four different lectin domains. The lectin domains of GalNAc-T1, -T2, -T3, and -T4 bound different subsets of small glycopeptides. These results indicate an additional level of complexity in the initiation step of O-glycosylation by GalNAc-Ts.

AB - UDP-GalNAc:polypeptide α-N-acetylgalactosaminyltransferases (GalNAc-Ts) constitute a family of up to 20 transferases that initiate mucin-type O-glycosylation. The transferases are structurally composed of catalytic and lectin domains. Two modes have been identified for the selection of glycosylation sites by GalNAc-Ts: confined sequence recognition by the catalytic domain alone, and concerted recognition of acceptor sites and adjacent GalNAc-glycosylated sites by the catalytic and lectin domains, respectively. Thus far, only the catalytic domain has been shown to have peptide sequence specificity, whereas the primary function of the lectin domain is to increase affinity to previously glycosylated substrates. Whether the lectin domain also has peptide sequence selectivity has remained unclear. Using a glycopeptide array with a library of synthetic and recombinant glycopeptides based on sequences of mucins MUC1, MUC2, MUC4, MUC5AC, MUC6, and MUC7 as well as a random glycopeptide bead library, we examined the binding properties of four different lectin domains. The lectin domains of GalNAc-T1, -T2, -T3, and -T4 bound different subsets of small glycopeptides. These results indicate an additional level of complexity in the initiation step of O-glycosylation by GalNAc-Ts.

U2 - 10.1074/jbc.M111.273722

DO - 10.1074/jbc.M111.273722

M3 - Journal article

C2 - 21768105

SN - 1083-351X

VL - 286

SP - 32684

EP - 32696

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

IS - 37

ER -