Hellow Everyone,

I am currently trying to look at the effects that graphene oxide might have on the amyloidogenic proteins such as amylin.

I've tried to model graphene oxide in Forcite using the COMPASS II force field, and the parameters seems to work fine with the funtional groups present.

However, when I introduce the amylin protein into the system and running geometery optimization, the C-O bonds on my protein started to elongate by an exagerated amount (seen in attachments).

I'm just wondering if this is a bug? Or is it that COMPASS II does not have appropriate parameters for this type of bonds?

Included is an attachment showing the problem I'm having, with all the waters in the cell hiden for better illustration.

Any help will be much appreciated, thanks.

Enxi Peng