Hi all!<br><br>I`m working on tRNA MD. My structure contains modified base 2MG, which have been added to the ffamber99p.rtp:<br><br>[2MG]<br> [atoms]<br> P amber99_46 1.08783 1<br> O1P amber99_45 -0.76666
2<br> O2P amber99_45 -0.76666 3<br> O5' amber99_44 -0.47131 4<br> C5' amber99_11 0.06353 5<br> H5'1 amber99_19 0.06892 6<br> H5'2 amber99_19 0.06892 7
<br> C4' amber99_11 0.03859 8<br> O4' amber99_44 -0.32723 9<br> C1' amber99_11 0.04596 10<br> C2' amber99_11 0.07745 11<br> O2' amber99_43 -0.59135 12
<br> HO'2 amber99_25 0.41014 13<br> H2' amber99_19 0.09290 14<br> N9 amber99_40 -0.00919 15<br> C8 amber99_6 0.10447 16<br> N7 amber99_36 -0.55207 17<br> C5 amber99_4
0.13484 18<br> C6 amber99_2 0.58227 19<br> O6 amber99_41 -0.55183 20<br> N1 amber99_35 -0.60808 21<br> C2 amber99_3 0.65874 22<br> N2 amber99_38 -0.55992 23<br>
H21 amber99_17 0.35843 24<br> C10 amber99_11 -0.07537 25<br> H20 amber99_19 0.08216 26<br> H21 amber99_19 0.08216 27<br> H22 amber99_19 0.08216 28<br> N3 amber99_37 -
0.54563 29<br> C4 amber99_4 0.19346 30<br> H1 amber99_17 0.34611 31<br> H8 amber99_24 0.15910 32<br> H1' amber99_20 0.16432 33<br> H4' amber99_19 0.11682
34
<br> C3' amber99_11 0.21246 35<br> H3' amber99_19 0.08253 36<br> O3' amber99_44 -0.48898 37<br><br> [bonds]<br>...<br>...<br><br>After pdb2gmx -f trna.pdb -o trna.gro -v Gromacs says:
<br><br>WARNING: atom H5'1 is missing in residue 2MG 1 in the pdb file<br> You might need to add atom H5'1 to the hydrogen database of residue 2MG<br> in the file ff???.hdb (see the manual)<br>WARNING: atom H5'2 is missing in residue 2MG 1 in the pdb file
<br> You might need to add atom H5'2 to the hydrogen database of residue 2MG<br> in the file ff???.hdb (see the manual)<br>...<br>...<br>I try to study hdb file by comparing .rtp, .pdb, and .hdb- entries, but my PDB structure does not contain any H-atoms.
<br>Where can I read about .hdb entry format for AMBER forcefield?<br>