Characterizing the binding site of the sialyltransferase ST6Gal1 using NMR of bound sugar nucleotide analogs

CARB 63

Shan Liu, sliu@uga.edu and James H. Prestegard, jpresteg@ccrc.uga.edu. Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602
The alpha-2,6-sialyltransferase, ST6Gal1, is a structurally uncharacterized glycosylated protein of biomedical importance. While direct structure determination by NMR remains a challenge, much can be deduced about active site geometry from NMR studies of bound ligand analogs. Here we report the use of STD and trNOE experiments to investigate the bound geometries of the natural donor, CMP-NeuAc, and its unhydrolyzable analog CMP-3FNeuAc, RDC experiments to determine the orientation of substrates using isotopically labeled CMP-NeuAc, and paramagnetic relaxation enhancement experiments to identify binding site residues and distances between donor and acceptor using a TEMPO analog of CMP-NeuAc. The latter is dependent on new strategies for the assignment of resonances in sparsely 15N labeled proteins expressed in eukaryotic hosts. This ongoing work will improve our structural understanding of ST6Gal1 and provide a framework for the structural-based design of specific inhibitors.
 

General Posters
6:00 PM-8:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix

Division of Carbohydrate Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007