Yes, DISCO search recognizes the (@) symbol as an email address. An easy way to search for all emails from a certain domain is to use the Search Builder. Navigate to the search screen and click on the search bar. The search helpers will appear. Use the default Search Builder to craft your search.
From the select bar, choose the field Email Domain. Select the specific email domain and add to your search query by clicking the blue button Add Search Term. To run the search, click the magnifying glass icon to the far right or hit the Enter button on your keyboard.