[1] Univ Maryland, Inst Biotechnol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA
[2] Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA USA
[3] Univ Roma La Sapienza, Inst Pasteur, Fdn Cenci Bolognetti, Rome, Italy
[4] Columbia Univ, CUBIC, Dept Biochem & Mol Biophys, New York, NY USA