Do change same protein (11)
I believe the answer is:
impersonate
'do' is the definition.
(thesaurus)
'change same protein' is the wordplay.
'change' indicates an anagram.
'same'+'protein'='sameprotein'
'sameprotein' anagrammed gives 'IMPERSONATE'.
(Other definitions for impersonate that I've seen before include "Pinch identity of" , "Copy" , "Assume character of another - no spare time (anag)" , "Pretend to be (another person)" , "Take off" .)