# Error: atom C1 not found in buiding block 1MET while combining tdb and rtp

**URL:** <https://gromacs.bioexcel.eu/t/error-atom-c1-not-found-in-buiding-block-1met-while-combining-tdb-and-rtp/7265>\
**Category:** User discussions\
**Tags:** pdb2gmx, forcefield\
**Created:** [September 26, 2023, 1:59pm UTC](https://gromacs.bioexcel.eu/t/error-atom-c1-not-found-in-buiding-block-1met-while-combining-tdb-and-rtp/7265 "2023-09-26T13:59:42Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![al42and](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/al42and/32/1393_2.png) [@al42and](https://gromacs.bioexcel.eu/u/al42and)\
**Post date:** [September 26, 2023, 2:22pm UTC](https://gromacs.bioexcel.eu/t/error-atom-c1-not-found-in-buiding-block-1met-while-combining-tdb-and-rtp/7265/2 "2023-09-26T14:22:10Z")

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Hi!

Have you tried using the `-ter` option to choose the proper terminii, as suggested in [several](https://gromacs.bioexcel.eu/t/protein-ligand-complex-tutorial-errors/6056/3) [other](https://gromacs.bioexcel.eu/t/atom-c1-not-found-in-building-block-pdb2gmx-fatal-error/5206/2) [topics](https://gromacs.bioexcel.eu/t/newest-charmm36-port-for-gromacs/868/14)?

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_[View the full topic](https://gromacs.bioexcel.eu/t/error-atom-c1-not-found-in-buiding-block-1met-while-combining-tdb-and-rtp/7265)._