I can reproduce this. Coot 0.6.2 3562, CCP4 6.2.0, installed using fink on OS X 10.6.8
There are 2 data in /sw64/share/coot/lib/data/monomers/g/GR.cif There are 2 data in /sw64/share/coot/lib/data/monomers/g/GD.cif I have the same B-factors for G as in Francis' e-mail so I guess we have the same monomer library - it seems odd that those for the ribose/phosphate are so different from the base: (2) P /1/A/1/G, occ: 1 with B-factor: 76.88 element: " P" at (39.6844,26.275,26.2063) (2) OP1/1/A/1/G, occ: 1 with B-factor: 78.59 element: " O" at (40.52,26.881,27.2727) (2) OP2/1/A/1/G, occ: 1 with B-factor: 75.2 element: " O" at (39.2682,24.8627,26.2543) (2) O5'/1/A/1/G, occ: 1 with B-factor: 78.76 element: " O" at (38.3451,27.1357,26.0928) (2) C5'/1/A/1/G, occ: 1 with B-factor: 77.93 element: " C" at (38.2659,28.5225,26.4572) (2) C4'/1/A/1/G, occ: 1 with B-factor: 78.66 element: " C" at (36.8162,28.983,26.4403) (2) O4'/1/A/1/G, occ: 1 with B-factor: 79.49 element: " O" at (36.185,28.7155,25.1419) (2) C3'/1/A/1/G, occ: 1 with B-factor: 78.23 element: " C" at (35.9012,28.308,27.4549) (2) O3'/1/A/1/G, occ: 1 with B-factor: 77.17 element: " O" at (36.069,28.919,28.7417) (2) C2'/1/A/1/G, occ: 1 with B-factor: 79.34 element: " C" at (34.5327,28.5477,26.7906) (2) O2'/1/A/1/G, occ: 1 with B-factor: 79.34 element: " O" at (34.0297,29.8752,26.9092) (2) C1'/1/A/1/G, occ: 1 with B-factor: 78.22 element: " C" at (34.8445,28.2835,25.3134) (2) N9 /1/A/1/G, occ: 1 with B-factor: 20 element: " N" at (34.6664,26.8914,24.8618) (2) C8 /1/A/1/G, occ: 1 with B-factor: 20 element: " C" at (35.642,26.0221,24.4301) (2) N7 /1/A/1/G, occ: 1 with B-factor: 20 element: " N" at (35.1835,24.8398,24.0816) (2) C5 /1/A/1/G, occ: 1 with B-factor: 20 element: " C" at (33.8113,24.9174,24.2875) (2) C4 /1/A/1/G, occ: 1 with B-factor: 20 element: " C" at (33.4712,26.1664,24.7702) (2) N1 /1/A/1/G, occ: 1 with B-factor: 20 element: " N" at (31.5322,24.4256,24.4388) (2) C2 /1/A/1/G, occ: 1 with B-factor: 20 element: " C" at (31.2804,25.6882,24.9068) (2) N3 /1/A/1/G, occ: 1 with B-factor: 20 element: " N" at (32.2166,26.6043,25.0936) (2) C6 /1/A/1/G, occ: 1 with B-factor: 20 element: " C" at (32.7971,23.9412,24.1001) (2) O6 /1/A/1/G, occ: 1 with B-factor: 20 element: " O" at (32.9177,22.7756,23.6884) (2) N2 /1/A/1/G, occ: 1 with B-factor: 20 element: " N" at (30.0137,25.9864,25.1789) Is this only an issue with the fink distributed Coot? Huw -- Dr Huw Jenkins University of Leeds Leeds, LS2 9JT