1. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
2. Joint BioEnergy Institute, Emeryville, California 94608, United States
3. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
4. Department of Wood Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
5. Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
6. BioSciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States