1. Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, Department of Plant Biochemistry, University of Neuchâtel, Neuchâtel CH-2007, Switzerland, Institute of Biotechnology of Plants, University of Paris-South, Orsay Cedex 91405, France, Laboratory of Forest Biology, Associe INRA, University of Nancy 1, 54506 Vandoeuvre Cedex, France, and Life Sciences Division, Protein Engineering Program, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831