Converts not bearing right in backstreet (5)
I believe the answer is:
turns
'converts' is the definition.
('turn' can be a synonym of 'convert')
'not bearing right in backstreet' is the wordplay.
'not' becomes 'un' (prefix meaning 'not').
'bearing' is an insertion indicator.
'right' becomes 'r' (common abbreviation).
'in' is an insertion indicator.
'backstreet' becomes 'ts' ('st' backwards).
'un' going around 'r' is 'urn'.
'urn' inserted inside 'ts' is 'TURNS'.
(Other definitions for turns that I've seen before include "Bends" , "Starts" , "Rotations" , "Changes direction" , "Revolves" .)