# Problem in shrinking step for area per lipid during TM protein simulation

**URL:** <https://gromacs.bioexcel.eu/t/problem-in-shrinking-step-for-area-per-lipid-during-tm-protein-simulation/2696>\
**Category:** User discussions\
**Created:** [August 19, 2021, 4:28am UTC](https://gromacs.bioexcel.eu/t/problem-in-shrinking-step-for-area-per-lipid-during-tm-protein-simulation/2696 "2021-08-19T04:28:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![zeeshan](https://avatars.discourse-cdn.com/v4/letter/z/c4cdca/32.png) [@zeeshan](https://gromacs.bioexcel.eu/u/zeeshan)\
**Post date:** [August 19, 2021, 4:28am UTC](https://gromacs.bioexcel.eu/t/problem-in-shrinking-step-for-area-per-lipid-during-tm-protein-simulation/2696/1 "2021-08-19T04:28:58Z")

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GROMACS version:5.1  
GROMACS modification: No  
Here post your question  
Hi. I am running transmembrane protein simulation. I am confused at position restraining. During the shrinking steps using [inflategro.pl](https://www.researchgate.net/deref/http%3A%2F%2Finflategro.pl) script, tutorial mentions experimental value 0.69A but i do not experimental value in my case. Please help me about how many iterations I should perform?