1. Large-Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
2. Department of Biochemistry, and Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States
3. Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
4. Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee 37966, United States