Turn over where e-books deteriorate (7)
I believe the answer is:
entrust
'turn over' is the definition.
(entrusting is a kind of turning over)
'e-books deteriorate' is the wordplay.
'books' becomes 'nt' (New Testament).
'deteriorate' becomes 'rust' (I've seen this before).
'e'+'nt'+'rust'='ENTRUST'
'where' acts as a link.
(Other definitions for entrust that I've seen before include "Invest, commit" , "Commend" , "Place in someone's 22 ac" , "Place in someone's care for test run" , "Give as responsibility, place in care of" .)