Table 1.

Description of different mechanisms of facilitated diffusion.

Name	Description
Jumps/3D search	The protein explores the space in the cytosol or solution through 3D Brownian motion. Non-specific binding is followed by the protein dissociating. Subsequent binding to other sites occurs in an uncorrelated manner.
Sliding	The protein binds non-specifically to DNA/RNA and undergoes a movement which is characterized by a tight interaction with the nucleic acid molecule. The protein stays associated to the substrate at all times. In the words of Berg, no net displacement of counterions takes place here and therefore the time spent on non-specific substrate is not affected by a change in the ionic concentration in the surroundings.
Hopping	This mode is characterized by micro-dissociations from the DNA/RNA strand. While the method of diffusion is similar to 3D search, the difference is that the movements are correlated along the contour of the strand. Contrary to sliding, not every base is scanned in the effectively covered distance. Since the protein dissociates momentarily from the strand, condensation of counterions is allowed to occur. Hence the time spent on non-specific DNA is expected to decrease by increased ionic strength.
Intersegmental transfer	The protein with multiple binding sites is bound to one strand. In a hand-over process, the protein can be momentarily bound to two strands through interaction with its binding site, after which it moves to the other strand.