# Mg elemental ion "unspecified charge" ERROR **URL:** \ **Category:** HADDOCK\ **Created:** [March 25, 2021, 2:56pm UTC](https://ask.bioexcel.eu/t/mg-elemental-ion-unspecified-charge-error/2867 "2021-03-25T14:56:59Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![leon\_michalski](https://avatars.discourse-cdn.com/v4/letter/l/4da419/32.png) [@leon\_michalski](https://ask.bioexcel.eu/u/leon_michalski)\ **Post date:** [March 25, 2021, 2:56pm UTC](https://ask.bioexcel.eu/t/mg-elemental-ion-unspecified-charge-error/2867/1 "2021-03-25T14:56:59Z")
Hello, I am trying to dock two proteins, 1 with a Mg atom. HADDOCK 2.4 sends an error when I input my files “your PDB contains an elemental ion MG without specified charge”. When I try to name my atom MG2+, and residue MG2 in the PDB the column is shifted and the formatting is incorrect. How do I resolve this? (Mg2+ ions is an important element of the GTPase protein) Sincerely, LFM ---
**Author:** ![honoratorv](https://dub1.discourse-cdn.com/flex013/user_avatar/ask.bioexcel.eu/honoratorv/32/672_2.png) [@honoratorv](https://ask.bioexcel.eu/u/honoratorv)\ **Post date:** [March 25, 2021, 7:42pm UTC](https://ask.bioexcel.eu/t/mg-elemental-ion-unspecified-charge-error/2867/2 "2021-03-25T19:42:14Z")
In our Library page you can see more information about the ion formatting, please have a look: [HADDOCK Web Server - Settings](https://bianca.science.uu.nl/haddock2.4/library). > [@leon\_michalski](#): > > When I try to name my atom MG2+, and residue MG2 in the PDB the column is shifted and the formatting is incorrect. How do I resolve this? (Mg2+ ions is an important element of the GTPase protein) Have a look at the PDB file format documentation if you need help figuring out where the spaces should be. [https://www.wwpdb.org/documentation/file-format-content/format33/v3.3.html](https://www.wwpdb.org/documentation/file-format-content/format33/v3.3.html) Good luck!