# OH group carbohydrate error

**URL:** <https://ask.bioexcel.eu/t/oh-group-carbohydrate-error/372>\
**Category:** HADDOCK\
**Created:** [May 24, 2017, 1:31pm UTC](https://ask.bioexcel.eu/t/oh-group-carbohydrate-error/372 "2017-05-24T13:31:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![lhutten](https://avatars.discourse-cdn.com/v4/letter/l/c6cbf5/32.png) [@lhutten](https://ask.bioexcel.eu/u/lhutten)\
**Post date:** [May 24, 2017, 1:31pm UTC](https://ask.bioexcel.eu/t/oh-group-carbohydrate-error/372/1 "2017-05-24T13:31:05Z")

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For a project I need to first bind a certain carbohydrate (that we made with glycam) to a protein, and then make a complex of the protein+carbohydrate and LDLR. However to test if it runs in HADDOCK I tried to make a complex of the carbohydrate and my protein. But the OH group (which is necessary for the project) causes a problem. I get the following error:

**Unable to generate topology for ligand ROH. PRODRG did not create the required output:**  
**PRODRG\>WARNING: deleted hydrogen HO1 from your input.**

In SPDB Viewer the OH group makes a triangle with itself somehow (the H atoms form an extra bond with the nearby O and C atoms) which is why this error occurs I assume. Is there a way to solve this?

Thank you.