Jan Jensen edited In_the_case_of_GB3__.tex  over 8 years ago

Commit id: 99c383b138e708988e85099788e86c2ff81f40a0

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In the case of GB3 the RMSD ($r$) value for C$\beta$ can be reduced (increased) to 1.8 ppm (0.71) by removing a single outlier identified by the Generalized Extreme Studentized Deviate Test. The outlier is Ala20 for which ProCS15 and DFT predict a C$\beta$ chemical shielding value of 176.8 and 167.4 ppm, respectively. Inspection of the structure shows that the C$\beta$ atom is only 3.1 Å from the N atom of Ala26 - an interaction not taken into account in the parameterization of ProCS15.   Similarly (also for GB3), the RMSD ($r$) value for H can be reduced (increased) to 0.6 ppm (0.91) by removing a single outlier identified by the Generalized Extreme Studentized Deviate Test. The outlier is Gln2 for which ProCS15 and DFT predict a H$^\text{N}$ chemical shielding value of 24.2 and 20.1 ppm, respectively. Inspection of the structure shows that the H$^\text{N}$ atom is within 1.77 Å of the OE1 atom of the Gln side chain and with 2.54 Å of an H$\varepsilon$ atom of the Met1 side chain. While the former interaction these interactions  should be included in the $\sigma_{BB}^{i}$ and $\Delta \sigma_{BB}^{i-1}$  term, respectively, it i possible that  the latter interaction is not and may be responsible for found in the scan due to  the large deviation. choice of $\phi_{text{std}}$ and $\psi_{text{std}}$ described above.  This residue is also identified as an outlier for N and removing it reduces (increases) the RMSD ($r$) value to 4.1 ppm (0.81).