# Converting Zwitterions to neutral molecules

**URL:** <https://discuss.avogadro.cc/t/converting-zwitterions-to-neutral-molecules/382>\
**Category:** General Discussion\
**Created:** [January 1, 2015, 12:40am UTC](https://discuss.avogadro.cc/t/converting-zwitterions-to-neutral-molecules/382 "2015-01-01T00:40:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Brenton\_Horne](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/brenton_horne/32/187_2.png) [@Brenton\_Horne](https://discuss.avogadro.cc/u/Brenton_Horne)\
**Post date:** [January 1, 2015, 12:40am UTC](https://discuss.avogadro.cc/t/converting-zwitterions-to-neutral-molecules/382/1 "2015-01-01T00:40:23Z")

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Hi,

I’ve been trying to create 3D models of amino acids based on PDB  
structures of them as the free ligand and I’d like to know how I could  
convert Zwitterions to neutral molecules in Avogadro.

Thanks for your time,  
Brenton

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<div class="post-metadata">

**Author:** ![ghutchis](https://discuss.avogadro.cc/user_avatar/discuss.avogadro.cc/ghutchis/32/456_2.png) [@ghutchis](https://discuss.avogadro.cc/u/ghutchis)\
**Post date:** [January 2, 2015, 12:58am UTC](https://discuss.avogadro.cc/t/converting-zwitterions-to-neutral-molecules/382/2 "2015-01-02T00:58:29Z")

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Avogadro has an “Add Hydrogens” command:

Build → Add Hydrogens

Hope that helps,  
-Geoff

> I’ve been trying to create 3D models of amino acids based on PDB  
> structures of them as the free ligand and I’d like to know how I could  
> convert Zwitterions to neutral molecules in Avogadro.