Hi,
I am aware that extended conjugated systems are a real challenge for
conventional forces fields and 'difficult' at best. But I still keep
wondering if a force field like GAFF could give any valuable insights
- possibly through carefully handcrafted parameters.
I am interested in a particular xantophyll and have observed that
rotations around single bonds in the isoprene units are quite frequent,
also in the protein environment which would lead to destabilisation of
the complex and, I would think, is unreasonable. Probably I should
also mention that I lazily used AM1BCC charges due to the large size
(about 100 atoms).
I have one study here that uses OPLS parameters for beta-carotene
inserted in a membrane bilayer. Rotations in single bonds are reported
to be quite infrequent.
Cheers,
Hannes.
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Received on Fri Sep 03 2010 - 07:00:04 PDT
