2rst

Publication Abstract from PubMed

The C-terminal domain (Ch; C-half) of the R-type earthworm 29-kDa lectin (EW29), isolated from the earthworm Lumbricus terrestris, has two sugar-binding sites, in subdomains alpha and gamma, and the protein uses the two sugar-binding sites for its function as a single domain-type haemagglutinin. Our previous NMR titration experiments showed that the alpha sugar-binding site is a high-affinity site and the gamma sugar-binding site is a low-affinity site. However, it remains unclear why the alpha sugar-binding site of EW29Ch binds to lactose much more strongly because the crystal structure of lactose-bound EW29Ch showed that the interaction between the alpha sugar-binding site and lactose was almost same as that between the gamma sugar-binding site and lactose. In the present study, we have determined the NMR structure of EW29Ch in the sugar-free state and performed (15)N relaxation experiments for EW29Ch in both the sugar-free state and the lactose-bound states. The conformation of EW29Ch in the sugar-free state was similar to that of EW29Ch in complex with lactose. Conformational changes upon binding of lactose were observed only for the alpha sugar-binding site. By contrast, the (15)N relaxation experiments revealed a conformational exchange at the alpha sugar-binding site in the sugar-free state, which was suppressed in the lactose-bound state. The conformational exchange phenomenon observed for the alpha sugar-binding site was not observed for the gamma sugar-binding site. Differences in the conformational change and the backbone dynamics between subdomains alpha and gamma may be associated with the difference of the sugar-binding modes between the two sugar-binding sites. DATABASE: Structural data for the NMR structure of EW29Ch in the sugar-free state have been deposited in the Protein Data Bank database under accession number 2RST.

NMR structure and dynamics of the C-terminal domain of R-type lectin from the earthworm Lumbricus terrestris.,Hemmi H, Kuno A, Hirabayashi J FEBS J. 2013 Jan;280(1):70-82. doi: 10.1111/febs.12050. Epub 2012 Nov 23. PMID:23122331^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.