00386nam a2200121Ia 4500008004100000022001400041040001100055100002700066245008400093260006200177300001600239300000900255251112s9999||||xx |||||||||||||| ||und||  a0027-8424  aCNCLSA  aNicholas R. Cozzarelli 0aProceedings Of The National Academy Of Sciences Of The United States Of America  cJuly 6, 1999bThe National Academy Of ScienceaWashington  aP.7611-8800  bV.96