how to associate .pdb files as plain text ?

as a long time macosx user (since NeXT), my favorite text editor is xcode.

this started recently. every time i open a .pdb (a protein data bank not a debug symbols file) in xcode, it shows an icon instead of text.

how do i set up to open .pdb files as PLAIN TEXT ??

it's really annoying to have to go to file inspector every time i open a .pdb file, scroll down multiple pages to select to "plain text"

i looked into xcode.app/contents/info.plist, nothing there