Tus (biology)
![Representation of the x-ray crystal structure of Tus-Ter protein-DNA complex. (Jmol rendering of coordinates from.[1] The DNA strands are shown in pink and green.)](/Images/godic/202502/18/Tus-Ter_complex_1ecr0245.png")
Tus, also known as terminus utilization substance, is a protein that binds to terminator sequences and acts as a counter-helicase when it comes in contact with an advancing helicase. The bound Tus protein effectively halts DNA polymerase movement. Tus helps end DNA replication in prokaryotes.