Atomic-resolution crystal structures of the immune protein conglutinin from cow reveal specific interactions of its binding site with <i>N</i>-acetylglucosamine.

ABSTRACT: Bovine conglutinin is an immune protein that is involved in host resistance to microbes and parasites and interacts with complement component iC3b, agglutinates erythrocytes, and neutralizes influenza A virus. Here, we determined the high-resolution (0.97-1.46 Å) crystal structures with and without bound ligand of a recombinant fragment of conglutinin's C-terminal carbohydrate-recognition domain (CRD). The structures disclosed that the high-affinity ligand N-acetyl-d-glucosamine (GlcNAc) binds in the collectin CRD calcium site by interacting with the O3' and O4' hydroxyls alongside additional specific interactions of the N-acetyl group oxygen and nitrogen with Lys-343 and Asp-320, respectively. These residues, unique to conglutinin and differing both in sequence and in locati

SUBMITTER: Paterson JM 

PROVIDER: S-EPMC6851296 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature