Which of the Following Is NOT True About the Substrate-Binding

Multiple Choice

Which of the following is NOT true about the substrate-binding protein (SBP) of the ABC transport system?

A) It is found in the periplasm of Gram-negative cells.
B) It is found tethered in Gram-positive cells.
C) It binds to the periplasmic face of the channel and releases the solute.
D) It snags the appropriate solute.
E) It is required for both the uptake and efflux systems.