PMID: 20506248

Authors:

Kowatz T, Morrison JP, Tanner ME, Naismith JH

Title:

The crystal structure of the Y140F mutant of ADP-L-glycero-D-manno-heptose 6-epimerase bound to ADP-beta-D-mannose suggests a one base mechanism.

Journal:

Protein Sci. 2010 May 5.

Abstract:

Bacteria synthesise a wide array of unusual carbohydrate molecules which they use in a variety of ways. The carbohydrate L-glycero-D-manno-heptose is an important component of lipopolysaccharide and is synthesised in a complex series of enzymatic steps. One step involves the epimerisation at the C6'' position converting ADP-D-glycero-D-manno-heptose into ADP-L-glycero-D-manno-heptose. The enzyme responsible is a member of the short chain dehydrogenase superfamily, known as ADP-L-glycero-D-manno-heptose 6-epimerase (AGME). The structure of the enzyme was known but the arrangement of the catalytic site with respect to the substrate is unclear. We now report the structure of AGME bound to a substrate mimic, ADP-beta-D-mannose, which has the same stereochemical configuration as the substrate. The complex identifies the key residues and allows mechanistic insight into this novel enzyme.