[gmx-users] strange structure after energy minimization

[Albert]

Hello,

I've performed a energy minimization in Gromacs 2018v4. The structure
looked very strange after energy minimization:

There is a big gap in the structure for residue 400-450, which is missing
in the initial crystal structure. After energy minimization, gromacs
connected residue 399 to 451 with a covalent bond. Here is a screenshot for
the structure before and after the energy minimization:

http://www.gpcrm.org/tmp/gmx/1.jpg

I am just wondering how shall we solve this problem?

thanks a lot