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. Author manuscript; available in PMC: 2011 Jul 23.
Published in final edited form as: J Mol Biol. 2010 May 24;400(4):755–767. doi: 10.1016/j.jmb.2010.05.044

Figure 5.

Figure 5

Motions at μs - ms timescale in inteins. 15N R2/R1values are plotted versus amide proton-nitrogen residual dipolar coupling, DHN, for ΔΔIhh-V67CM (a) and Δ ΔIhh-L67CM (b). L428 and T430 clearly have contributions from chemical exchange due to motions at μs to ms timescale. (c) Temperature dependence of 15N-1H HSQC. The H429 peak becomes stronger at higher temperature, demonstrating the effect of chemical exchange and the transition from intermediate to fast timescale for chemical exchange with increasing temperature. (d) NH2 groups in 15N-1H HSQC of inteins. The cross peaks for the NH2 group of N440 are much weaker than other peaks and those of Q51, suggesting the effect of chemical exchange. (e) CPMG dispersion curve for E426 obtained at 293 K and at both 800 MHz (solid circles ‘●’) and 600 MHz (open circles ‘○ ’) and their associated fitting curves. (e) CPMG curve for A65 obtained at 293 K and at both 800 MHz (solid circles ‘● ’) and 600 MHz (open circles ‘○ ’) shows no dispersions. (g) Locations of nitrogen nuclei experiencing μs - ms timescale motion in the intein structure. Amide nitrogen nuclei with Rex (blue spheres) are clustered near the turn formed by the hydrogen bond (red dashed line) between E426 CO and H429 NH. Residues with Rex, including amides of conserved H429 and N440 are located at the C-terminal splicing junction. It is noteworthy that the N-terminal splicing junction (C1) is nearby as well.