Institution: | a Institute of Molecular Physiology, Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK b School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK c Electron Microscopy Center, Department of Biology and Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2257, USA |