1. Teva Branded Pharmaceutical Products R&D, Inc., West Chester, Pennsylvania 19380;
2. Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107;
3. Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama, Birmingham, Alabama 35294;
4. Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan 61-704, Poland
5. Center for Genome Research, Institute of Biosciences and Technology, Texas A&M University, Houston, Texas 77005;