[gmx-users] Why gyration radius keep dropping?

[ZHANG Cheng]

Dear Gromacs,
I am running MD at 500 K for my protein. 


I used this to analyse the gyration radius
echo 1 | gmx gyrate -s md_0_1.tpr -f md_0_1_noPBC.xtc -o gyrate.xvg


I thought the radius should keep increase, as the protein unfolds at high temperature. However, all my repeats showed a dropping in the gyration radius, from ~2.6 nm to ~2.2 nm in 50 ns.


Can I ask if this phenomenon is common?


Cheng