Improved crystallization of
Abstract:The bacterial ATP synthase (FOF1) of Escherichia coli has been the prominent model system for genetics, biochemical and more recently single‐molecule studies on F‐type ATP synthases. With 22 total polypeptide chains (total mass of ∼529 kDa), E. coli FOF1 represents nature's smallest rotary motor, composed of a membrane‐embedded proton transporter (FO) and a peripheral catalytic complex (F1). The ATPase activity of isolated F1 is fully expressed by the α3β3γ `core', whereas single δ and ɛ subunits are required for structural and functional coupling of E. coli F1 to FO. In contrast to mitochondrial F1‐ATPases that have been determined to atomic resolution, the bacterial homologues have proven very difficult to crystallize. In this paper, we describe a biochemical strategy that led us to improve the crystallogenesis of the E. coli F1‐ATPase catalytic core. Destabilizing the compact conformation of ɛ's C‐terminal domain with a phosphomimetic mutation (ɛS65D) dramatically increased crystallization success and reproducibility, yielding crystals of E. coli F1 that diffract to ∼3.15 Å resolution.
Document Type: Research Article
Publication date: 2012-10-01