Within the supplied crambin alpha helix (residues 7-19, per this entry's own HELIX record), calculate the one-helical-turn Ca9-Ca13 (i, i+4) distance. Report the distance in angstrom to three decimal places.

Coordinates are in angstrom (1 nm = 10 angstrom). XYZ atom rows are one-based after the two header lines. Use the supplied coordinate snapshot without optimization or periodic wrapping. Use S0008 only: all 46 CA sites of 1CRN chain A, row i = residue A:i. Residues 9 and 13 both lie within the deposited helix span (residues 7-19), away from this entry's own flagged conformational irregularity at residues 17 and 19. Report the distance in angstrom to three decimals.

46
PDB 1CRN crambin, 46 CA sites, chain A, model 1; angstrom
C 16.967 12.784 4.338
C 13.856 11.469 6.066
C 13.660 10.707 9.787
C 10.646 8.991 11.408
C 9.448 9.034 15.012
C 8.673 5.314 15.279
C 8.912 2.083 13.258
C 5.145 2.209 12.453
C 5.598 5.767 11.082
C 8.496 4.609 8.837
C 6.500 1.584 7.565
C 3.545 3.935 6.751
C 5.929 6.358 5.055
C 7.331 3.607 2.791
C 3.782 2.599 1.742
C 2.890 6.285 1.126
C 5.895 6.489 -1.213
C 4.933 3.431 -3.326
C 2.792 5.376 -5.797
C 5.366 8.191 -6.018
C 3.767 10.609 -3.513
C 6.143 13.513 -2.696
C 8.114 13.103 0.500
C 6.614 16.317 1.913
C 3.074 14.894 1.756
C 4.180 11.549 3.187
C 5.879 13.502 6.026
C 2.691 15.221 7.194
C 0.715 12.045 6.657
C 2.986 9.994 8.950
C 4.769 12.336 11.360
C 8.140 11.694 9.635
C 10.280 14.760 8.823
C 12.552 15.877 6.036
C 15.930 17.454 6.941
C 18.635 18.861 4.738
C 21.452 16.969 6.513
C 22.019 13.242 7.020
C 21.936 12.911 10.809
C 18.504 12.312 12.298
C 17.924 13.421 15.877
C 17.334 10.956 18.691
C 13.564 11.573 18.836
C 13.257 10.745 15.081
C 15.445 7.667 15.246
C 13.512 5.395 12.878


Attachments:
S0008: item-0003-asset-1.xyz