high resolution structure of the ba3 cytochrome c oxidase from thermus thermophilus in a lipidic environment把细胞色素c氧化酶的高分辨率结构从栖热菌属酸奶在油脂的环境中.pdfVIP

High Resolution Structure of the ba3 Cytochrome c Oxidase from Thermus thermophilus in a Lipidic Environment 1. 1. 1 2 1 1 Theresa Tiefenbrunn , Wei Liu , Ying Chen , Vsevolod Katritch , C. David Stout , James A. Fee *, Vadim Cherezov1* 1 Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America, 2 Skaggs School of Pharmacy Pharmaceutical Sciences and San Diego Supercomputer Center, University of California, San Diego, La Jolla, California, United States of America Abstract The fundamental chemistry underpinning aerobic life on Earth involves reduction of dioxygen to water with concomitant proton translocation. This process is catalyzed by members of the heme-copper oxidase (HCO) superfamily. Despite the availability of crystal structures for all types of HCO, the mode of action for this enzyme is not understood at the atomic level, namely how vectorial H+ and e- transport are coupled. Toward addressing this problem, we report wild type and ˚ A120F mutant structures of the ba3-type cytochrome c oxidase from Thermus thermophilus at 1.8 A resolution. The enzyme has been crystallized from the lipidic cubic phase, which mimics the biological membrane environment. The structures reveal 20 ordered lipid molecules that occupy binding sites on the protein surface or mediate crystal packing interfaces. The interior of the protein encloses 53 water molecules, including 3 trapped in the designated K-path of proton transfer and 8 in a cluster seen also in A-type enzymes that likely functions in egress of