1. Joint BioEnergy Institute, Emeryville, California 94608
2. Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
3. Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
4. Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
5. Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
6. Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
7. Department of Bioengineering, University of California, Berkeley, California 94720