Re: [AMBER] Problem when using lipid14 force filed in Amber 11

From: Ross Walker <ross.rosswalker.co.uk>
Date: Tue, 19 Jan 2016 13:05:46 -0800

Hi Bin,

Ah - I read this better now - sorry I was reading POPC rather than POPS.

POPS is not supported in lipid14. It was in lipid11 and can be used with the rest of lipid11 with a constant surface tension term. It should not be mixed with lipid14 parameters. POPS support will be released as an update to lipid14 - we are waiting on publication. Current plan is to include it as part of AmberTools16.

Do NOT use lipid14_supp.lib it is dubious origin (basically a holding place for lipid11 parameters that were to be reparameterized in line with lipid14). It should never have been included in the released version of AmberTools.

Sorry for the confusion.

Either way do NOT load lipid14.dat and then lipid11.dat - this will over write all sorts of parameters and you'll get a weird mix. Lipid 11 and lipid 14 should not be considered to be mixable.

All the best
Ross

> On Jan 19, 2016, at 12:11 PM, Bin Wang <ben.wangbj.gmail.com> wrote:
>
> Dr. Walker,
>
> I did followed each step exactly in that tutorial, and unfortunately it did
> not work in my case from the conversion of format using that
> charmmlipid2amber.py program. The PS was not recognized in Amber. No TER
> was added after each WAT and K+ ion. Then Jean-Marc helped me added the
> lipid14_supp.lib and changed residue numbers of all lipids. But I still had
> pdb format problem. Then I correct all of the pdb format problem, and I
> still got the "Could not find bond parameter" problem. In short, this is
> how I spent several weeks and cannot find why the tutorial is not working.
> So far, I still think the problem is from one of the .dat or .lib file.
>
>
>
>
>
>
>
>
> charmmlipid2amber.py
>
> On Tue, Jan 19, 2016 at 2:06 PM, Ross Walker <ross.rosswalker.co.uk> wrote:
>
>> UGH!!!!
>>
>> No do NOT do this - who knows what crazy frankenstein combination of
>> parameters you will get doing something like this. :-(
>>
>> Please work through the following tutorial:
>> http://ambermd.org/tutorials/advanced/tutorial16/
>>
>> And follow each step exactly and see if this works. If it does not then it
>> suggests something is messed up with your AMBER installation.
>>
>> All the best
>> Ross
>>
>>> On Jan 19, 2016, at 10:40 AM, Bin Wang <ben.wangbj.gmail.com> wrote:
>>>
>>> Dr. Walker, Dr. Case, and Jean-Marc,
>>>
>>> Thank you all for your kindly help. This time I add all .lib and .dat
>> files
>>> I can find in the leapin, and it works. It is shown below.
>>>
>>> source leaprc.lipid14
>>> source leaprc.lipid11
>>> source leaprc.ff12SB
>>> loadoff /opt/amber14/dat/leap/lib/lipid11.lib
>>> loadoff /opt/amber14/dat/leap/lib/lipid14.lib
>>> loadoff /opt/amber14/dat/leap/lib/lipid14_supp.lib
>>> loadamberparams frcmod.ionsjc_tip3p
>>> loadamberparams /opt/amber14/dat/leap/parm/lipid14.dat
>>> loadamberparams /opt/amber14/dat/leap/parm/lipid11.dat
>>> m = loadpdb membrane.pdb
>>>
>>>
>>> I do need to read the manual more carefully.
>>> I guess I got all of these format problems because I use the charged
>> lipid
>>> molecule POPS?
>>>
>>>
>>>
>>>
>>> On Tue, Jan 19, 2016 at 12:05 PM, David A Case <david.case.rutgers.edu>
>>> wrote:
>>>
>>>> On Tue, Jan 19, 2016, Bin Wang wrote:
>>>>
>>>>>>> The leapin file I used is shown below:
>>>>>>> source leaprc.lipid14
>>>>>>> source leaprc.ff12SB
>>>>>>> loadoff /opt/amber14/dat/leap/lib/lipid14_supp.lib
>>>>>>> loadamberparams frcmod.ionsjc_tip3p
>>>>>>> m = loadpdb membrane.pdb
>>>>
>>>> You need to look carefully for errors in the first line. Just type
>>>> "tleap -f leaprc.lipid14" and look carefully for any error messages you
>>>> might get. Or, examine the leap.log file you have from the above, find
>>>> the lines that run loadamberparams on lipid14.dat, and look for any
>> errors
>>>> there.
>>>>
>>>> [Developers: we should consider the pros and cons of having errors in
>>>> loading
>>>> files be fatal -- that way the corresponding error messages would be
>> less
>>>> likely to missed. Downside is that some existing scripts will start to
>>>> fail...may be some other downsides as well.]
>>>>
>>>> ....dac
>>>>
>>>>
>>>> _______________________________________________
>>>> AMBER mailing list
>>>> AMBER.ambermd.org
>>>> http://lists.ambermd.org/mailman/listinfo/amber
>>>>
>>> _______________________________________________
>>> AMBER mailing list
>>> AMBER.ambermd.org
>>> http://lists.ambermd.org/mailman/listinfo/amber
>>
>>
>> _______________________________________________
>> AMBER mailing list
>> AMBER.ambermd.org
>> http://lists.ambermd.org/mailman/listinfo/amber
>>
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber


_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Tue Jan 19 2016 - 13:30:03 PST
Custom Search