# Error in PDB file. Unknown error: invalid literal for int() with base 10: '2+'
**URL:** https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306
**Category:** Uncategorized
**Created:** [May 8, 2023, 6:15am UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306 "2023-05-08T06:15:45Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@sdraga](https://ask.bioexcel.eu/u/sdraga)
#### Post date: [May 8, 2023, 6:15am UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/1 "2023-05-08T06:15:45Z")
Hello everyone,
I am encountering an error when trying to upload my receptor structure (that has a ZN ion). The zinc ion is properly formatted (last lines of the pdb file below):
TER 1618 SER B 202
HETATM 1619 ZN2+ ZN2 Z 203 25.111 69.456 13.562 1.00 13.00 Z N
END
What am I missing here? I have uploaded a very similar structure recently and it worked quite well.
I have also uploaded the structure below (renumbered so that it starts from res 1, and sent to `pdb_uniquname` and `pdb_tidy` and manually defined the ZN ion format before uploading).
Any help would be greatly appreciated!
Kind regards ,
S
[rec\_unq\_tidy.pdb](https://ask.bioexcel.eu/uploads/short-url/ywAYJ6eh5G4bIsxBFKWASEbYEzv.pdb) (256.0 KB)
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### Author:  [@amjjbonvin](https://ask.bioexcel.eu/u/amjjbonvin)
#### Post date: [May 8, 2023, 6:35am UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/2 "2023-05-08T06:35:04Z")
Carefully check the column alignment, comparing it to the protein part.
Also if the zinc ion belongs to the protein give it the same chain ID
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### Author:  [@sdraga](https://ask.bioexcel.eu/u/sdraga)
#### Post date: [May 8, 2023, 6:54am UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/3 "2023-05-08T06:54:15Z")
Thank you for your reply, Prof. Bonvin!
I have modified the chain ID to be identical with the protein (B) and things appear to be properly aligned as far as I can see, but the error persists.
It most likely has to do with the formatting, but it escapes me. Any suggestions?
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### Author:  [@sdraga](https://ask.bioexcel.eu/u/sdraga)
#### Post date: [May 8, 2023, 12:31pm UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/4 "2023-05-08T12:31:25Z")
a mistake staring me in the face: modified the line according to the HADDOCK format (ZN2+ changed to ZN+2), but still did not solve the problem:
```auto
HETATM 1618 ZN2+ ZN2 B 203 25.111 69.456 13.562 1.00 13.00 ZN
```
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### Author:  [@amjjbonvin](https://ask.bioexcel.eu/u/amjjbonvin)
#### Post date: [May 8, 2023, 1:00pm UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/5 "2023-05-08T13:00:14Z")
ZN2+ should be ZN+2 (if I am correct) 🙂
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### Author:  [@sdraga](https://ask.bioexcel.eu/u/sdraga)
#### Post date: [May 8, 2023, 3:24pm UTC](https://ask.bioexcel.eu/t/error-in-pdb-file-unknown-error-invalid-literal-for-int-with-base-10-2/4306/6 "2023-05-08T15:24:15Z")
Thank you, prof. Bonvin, that was indeed the problem!