Fig. 4. (a) The local environments of R14, R52, R95, R96, and R145 in the crystal structure of T4L99A (pdb: 3dmv). Hydrogen bonds are depicted as dotted lines. (b) ΔΔG‡ = ΔG‡(Arg) – ΔG‡(free) = –RT ln[kex(Arg)/kex(free)] as a function of temperature for the five arginine side chains in (a). ΔΔG‡ for R14, R52 and R96 were obtained using D-evolution (circles), while ΔΔG‡ for R95 and R145 were obtained from longitudinal exchange experiments (squares).
