I really have no idea from your post what you want to do.
To prevent a break before the search for .@ and to prevent one after, search for @.
In the change format set a character style that applies No Break.
Ok peter I'm making a template for indesign-server so i can't not edit the tekst. The template must do it so i'm trying to use grip.
Sorry grep ofcourse :)
That was a pair of GREP expressions. They can be used in a GREP style or as part of a Find/Change query.
.@ matches any character foloowed by the @ sign.
@. matches the @ sign followed by any character.