tokens: The SSB - poly ( dT ) affinity is too high to measure in buffers containing even 5 M NaCl ; however , in 1 . 8 - 2 . 5 M NaBr , we measure alpha log Kobsd / alpha log [ NaBr ] = - 5 . 7 + / - 0 . 7 , with a lower value of omega T / O = 130 + / - 70 .