[gmx-users] How to obtain a proper structure for glycine?

[ZHANG Cheng]

Dear Gromacs,
I would like to perform simulations for a protein with glycines. 


I think I should use "insert-molecules" as shown on
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin/gmx-tutorials/biphasic/01_genconf.html


So I went to PRODRG2 Server to obtain the glycine structure by "text drawing":


    O
    "
N-C-C-O


But I got a suggested structure of NH3-CH2-COO, instead of NH2-CH2-COOH. Can I ask why is that?


Thank you.


Yours sincerely
Cheng