Affiliation: | From the Departments of ‡Physics and Astronomy and ;¶Chemistry, Iowa State University, Ames, Iowa 50011.;the §Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon 97239, and ;the ‖Northeastern Collaborative Access Team and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, Illinois 60439 |