Yes, there are modifications that can effectively be used in the crosslinking of DNA to Proteins. The modifications 6-Thio-dG, 4-Thio-dT and 4-thio-dU are very effective at crosslinking DNA to Proteins. Unfortunately, these modifications are not offered in IDT's catalog, but that does not necessarily mean that IDT will not synthesize these oligos. IDT has a Non-Catalog committee that routinely reviews requests for modifications that are not available in the catalog.
If you would like to submit a request to the non-catalog committee, please send your sequences with the modification position marked, any yield or purity needs, your contact information and any references or additional information you have on the modification. This request can be submitted to firstname.lastname@example.org.