“…However, in cancer cells, irrespective of oxygen availability, glycolysis followed by production of lactate through LDH is the preferred pathway, enhancing the production of metabolic precursors required for biosynthesis of cellular macromolecules. The recognition in a growing number of cancers of the central role of both LDH A and B isoforms (Fiume et al, 2014; McCleland et al, 2013; Rodriguez et al, 2003) has driven the identification of small-molecule inhibitors, including mercaptocyclohex-2-enone derivatives that bind away from the NAD-binding pocket and are not competitive inhibitors (Dragovich et al, 2014), as well as sulfamoylquinoline benzoic acid derivatives, which compete with NAD binding to LDH (Billiard et al, 2013). To evaluate the potential of cryo-EM to determine structures of a small protein complex such as LDH and localize the binding sites of potential small-molecule inhibitors, we carried out cryo-EM analysis of LDH B in complex with GSK2837808A, a 650 Dalton compound in the quinoline 3-sulfonamide series (Billiard et al, 2013).…”