# Steered molecular dynamics
**URL:** https://ask.bioexcel.eu/t/steered-molecular-dynamics/1403
**Category:** GROMACS
**Created:** [February 1, 2019, 8:58am UTC](https://ask.bioexcel.eu/t/steered-molecular-dynamics/1403 "2019-02-01T08:58:39Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@harshitha](https://ask.bioexcel.eu/u/harshitha)
#### Post date: [February 1, 2019, 8:58am UTC](https://ask.bioexcel.eu/t/steered-molecular-dynamics/1403/1 "2019-02-01T08:58:39Z")
In gromacs umbrella sampling as it mentioned in pull code that pull along the z co-ordinate , but in my case the molecules pulling over the protein is not in a x axis ,y axis and z axis .it should be pull in between the x and y axis so how can i re frame my pull code
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### Author:  [@mabraham](https://ask.bioexcel.eu/u/mabraham)
#### Post date: [February 4, 2019, 1:40pm UTC](https://ask.bioexcel.eu/t/steered-molecular-dynamics/1403/2 "2019-02-04T13:40:53Z")
The pull coordinate directions in GROMACS can be in any linear direction, e.g. see [http://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#mdp-pull-coord1-vec](http://manual.gromacs.org/documentation/current/user-guide/mdp-options.html#mdp-pull-coord1-vec).
So, e.g. if you want to pull coordinate 2 in the direction between the x and y axis, then use
> pull-coord2-vec = 1.0, 1.0, 0.0