First of all I would like to thank Justin, for giving me a clue about
checking the bonds in "chain_C.itp" file. When I removed all those
unexpected bonds, minimization as successful. <br><br><br>To summarize,
I want to minimize a pentamer by imposing distance restraints in one of
the chains. This chain has 14 residues missing and the distance between
the end residues (residue 162 and 163 here) is 12 A (1.2 nm). These are
the steps I followed to run minimization using distance restraints<br><br>1. pdb2gmx -ff G43a1 -f chnr.pdb -o chnr1.gro -p chnr1.top -ter -his -ss -asp -glu -water spce<br><br> I didn't use -missing option, as I didn't observe any difference either way<br><br>2. Included the following distance restraints in the chain_C.itp file<br><br>#ifdef DISRES<br>[ distance_restraints ]<br>;ai aj type index type' low up1 up2 fac<br>1703 1712 1 0 1 1.15 1.20 1.25 1.0<br>#endif<br><br>3.
Removed unexpected bonds between the two residues. This is the step
which I skipped and has been giving me an error "Warning: 1-4
interaction between<br>6151 and 6160 is at distance 1.387 which is larger than the 1-4 table size". I end up in a structure with missing bonds.<br><br>Here is part of the chain_c.itp file with changes<br><br>; File 'chnrc_C.itp' was generated<br>; By user: onbekend (0)<br>; On host: onbekend<br>; At date: Thu Sep 4 10:58:17 2008<br>;<br>; This is your include topology file<br>; "I Feel a Great Disturbance in the Force" (The Emperor Strikes Back)<br>;<br>[ moleculetype ]<br>; Name nrexcl<br>Protein_C 3<br><br>[ atoms ]<br>; nr type resnr residue atom cgnr charge mass typeB chargeB massB<br> 1701 N 162 LEU N 733 -0.28 14.0067 ; qtot -7.28<br> 1702 H 162 LEU H 733 0.28 1.008 ; qtot -7<br> 1703 CH1 162 LEU CA 734 0 13.019 ; qtot -7<br> 1704 CH2 162 LEU CB 734 0 14.027 ; qtot -7<br> 1705 CH1 162 LEU CG 735 0 13.019 ; qtot -7<br> 1706 CH3 162 LEU CD1 735 0 15.035 ; qtot -7<br> 1707 CH3 162 LEU CD2 735 0 15.035 ; qtot -7<br> 1708 C 162 LEU C 736 0.38 12.011 ; qtot -6.62<br> 1709 O 162 LEU O 736 -0.38 15.9994 ; qtot -7<br> 1710 N 163 ILE N 737 -0.28 14.0067 ; qtot -7.28<br> 1711 H 163 ILE H 737 0.28 1.008 ; qtot -7<br> 1712 CH1 163 ILE CA 738 0 13.019 ; qtot -7<br> 1713 CH1 163 ILE CB 739 0 13.019 ; qtot -7<br> 1714 CH2 163 ILE CG1 739 0 14.027 ; qtot -7<br> 1715 CH3 163 ILE CG2 739 0 15.035 ; qtot -7<br> 1716 CH3 163 ILE CD 739 0 15.035 ; qtot -7<br> 1717 C 163 ILE C 740 0.38 12.011 ; qtot -6.62<br> 1718 O 163 ILE O 740 -0.38 15.9994 ; qtot -7<br> <br>[ bonds ]<br>; ai aj funct c0 c1 c2 c3<br> 1699 1701 2 gb_9<br> 1701 1702 2 gb_2<br> 1701 1703 2 gb_20<br> 1703 1704 2 gb_26<br> 1703 1708 2 gb_26<br> 1704 1705 2 gb_26<br> 1705 1706 2 gb_26<br> 1705 1707 2 gb_26<br> 1708 1709 2 gb_4<br> ;1708 1710 2 gb_9 <br> 1710 1711 2 gb_2<br> 1710 1712 2 gb_20<br> 1712 1713 2 gb_26<br> 1712 1717 2 gb_26<br> 1713 1714 2 gb_26<br> 1713 1715 2 gb_26<br> 1714 1716 2 gb_26<br> 1717 1718 2 gb_4<br> 1717 1719 2 gb_9<br><br>[ pairs ]<br>; ai aj funct c0 c1 c2 c3<br> 1701 1705 1 <br> 1701 1709 1 <br> ;1701 1710 1 <br> 1702 1704 1 <br> 1702 1708 1 <br> 1703 1706 1 <br> 1703 1707 1 <br> ;1703 1711 1 <br> ;1703 1712 1 <br> 1704 1709 1 <br> ;1704 1710 1 <br> 1705 1708 1 <br> ;1708 1713 1 <br> ;1708 1717 1 <br> ;1709 1711 1 <br> ;1709 1712 1 <br> 1710 1714 1 <br> 1710 1715 1 <br> 1710 1718 1 <br> 1710 1719 1 <br> 1711 1713 1 <br> 1711 1717 1 <br> 1712 1716 1 <br> 1712 1720 1 <br> 1712 1721 1 <br> 1713 1718 1 <br> 1713 1719 1 <br> 1714 1717 1 <br> 1715 1716 1 <br> 1715 1717 1 <br> 1717 1722 1 <br> 1717 1726 1 <br> 1718 1720 1 <br> 1718 1721 1 <br><br>[ angles ]<br>; ai aj ak funct c0 c1 c2 c3<br> 1701 1703 1704 2 ga_12<br> 1701 1703 1708 2 ga_12<br> 1704 1703 1708 2 ga_12<br> 1703 1704 1705 2 ga_14<br> 1704 1705 1706 2 ga_14<br> 1704 1705 1707 2 ga_14<br> 1706 1705 1707 2 ga_14<br> 1703 1708 1709 2 ga_29<br> ;1703 1708 1710 2 ga_18<br> ;1709 1708 1710 2 ga_32<br> ;1708 1710 1711 2 ga_31<br> ;1708 1710 1712 2 ga_30<br> 1711 1710 1712 2 ga_17<br> 1710 1712 1713 2 ga_12<br> 1710 1712 1717 2 ga_12<br> 1713 1712 1717 2 ga_12<br> 1712 1713 1714 2 ga_14<br> 1712 1713 1715 2 ga_14<br> 1714 1713 1715 2 ga_14<br> 1713 1714 1716 2 ga_14<br> 1712 1717 1718 2 ga_29<br> 1712 1717 1719 2 ga_18<br> 1718 1717 1719 2 ga_32<br><br>[ dihedrals ]<br>; ai aj ak al funct c0 c1 c2 c3 c4 c5<br> <br> 1694 1699 1701 1703 1 gd_4<br> 1699 1701 1703 1708 1 gd_19<br> 1701 1703 1704 1705 1 gd_17<br> ;1701 1703 1708 1710 1 gd_20<br> 1703 1704 1705 1706 1 gd_17<br> ;1703 1708 1710 1712 1 gd_4<br> ;1708 1710 1712 1717 1 gd_19<br> 1710 1712 1713 1714 1 gd_17<br> 1710 1712 1717 1719 1 gd_20<br> 1712 1713 1714 1716 1 gd_17<br> 1712 1717 1719 1721 1 gd_4<br> 1717 1719 1721 1726 1 gd_19<br> 1719 1721 1722 1723 1 gd_17<br> 1719 1721 1726 1728 1 gd_20<br><br>[ dihedrals ]<br>; ai aj ak al funct c0 c1 c2 c3<br> 1701 1699 1703 1702 2 gi_1<br> 1703 1701 1708 1704 2 gi_2<br> 1704 1706 1707 1705 2 gi_2<br> ;1708 1703 1710 1709 2 gi_1<br> ;1710 1708 1712 1711 2 gi_1<br> 1712 1710 1717 1713 2 gi_2<br> 1712 1715 1714 1713 2 gi_2<br> 1717 1712 1719 1718 2 gi_1<br> 1719 1717 1721 1720 2 gi_1<br><br>#ifdef DISRES<br>[ distance_restraints ]<br>;ai aj type index type' low up1 up2 fac<br>1703 1712 1 0 1 1.15 1.20 1.25 1.0<br>#endif<br><br><br>4. Included "define = -DDISRES" in the .mdp file for minimisation<br><br> Once again, I appreciate Justin for giving me helpful hints in sorting out where I was going wrong.<br><br>Thanks & regards,<br>Latha.<br><br>>
So you have an incomplete protein backbone, with some odd numbering.
What command did you give pdb2gmx to generate this topology? Did you
use the -missing flag? If so, the topology may be badly broken and
unexpected bonds defined. Look closely at your [ bonds ] section in
"chain_C.itp" in case you have some bonds that you are not expecting!<br><br>I
checked the .itp file and I found some unexpected bonding between the
two residues. When, I removed all those bonds, it worked. <br><br>> Date: Wed, 03 Sep 2008 20:33:58 -0400<br>> From: "Justin A. Lemkul" <jalemkul@vt.edu><br>> Subject: Re: [gmx-users] Re: Bonds break while Minimising using<br>>         distance        restraints<br>> To: Discussion list for GROMACS users <gmx-users@gromacs.org><br>> Message-ID: <48BF2CF6.6070207@vt.edu><br>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed<br>> <br>> <br>> <br>> plmallip@mail.uh.edu wrote:<br>> <br>> > My protein has 5 chains. 1703 & 1712 are the numbers from <br>> chainC.itp <br>> > file. This includes the distance restraints -<br>> > <br>> > #ifdef DDISRES<br>> > [ distance_restraints ]<br>> > ;ai aj type index type' low up1 <br>> up2 fac<br>> > 1703 1712 1 0 <br>> 1 1.15 1.20 1.25 1.0<br>> > #endif<br>> > <br>> > 6151 & 6160 atoms are the numbers from .gro file reported by <br>> the .job <br>> > file. 6151 is N of residue 584 and 1703 is CA of the same <br>> redsidue. <br>> > Residue 584 & 585 are placed have 14 residues missing between <br>> them. 6160 <br>> > is N of residue 585 & 1712 is the corresponding CA.<br>> <br>> So you have an incomplete protein backbone, with some odd <br>> numbering. What <br>> command did you give pdb2gmx to generate this topology? <br>> Did you use the <br>> -missing flag? If so, the topology may be badly broken and <br>> unexpected bonds <br>> defined. Look closely at your [ bonds ] section in <br>> "chain_C.itp" in case you <br>> have some bonds that you are not expecting!<br>> <br>> Do you have complete residues for each of those that contain <br>> atoms 6151, 6160, <br>> 1703 and 1712? The non-sequential numbering (with 4000-<br>> atom separation!) does <br>> not indicate that these atoms should be in the same residues.<br>> <br>> Is your structure one that is available in the PDB? <br>> Perhaps it would be much <br>> easier to diagnose this if I could see the structure. I'd <br>> be willing to have a <br>> look at your structure file, if you'd like to send it to me <br>> privately. I'm <br>> somewhat intrigued as to what the problem is :)<br>> <br>> I would be willing to bet that there is something within that <br>> chain topology <br>> that is causing mdrun to find a 1-4 interaction between atoms <br>> 6151 and 6160.<br>> <br>> -Justin<br>> <br>> > <br>> > <br>> > Thanks & regards,<br>> > Latha.