1. National Institute of Standards and Technology, Material Measurement Laboratory, Biomolecular Measurement Division, Gaithersburg, MD 20899, USA
2. Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD 20850, USA
3. National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
4. Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
5. National Institute for Bioprocessing Research and Training, Foster Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland