The phrase "active entrance" is correct and usable in written English.
It can be used in contexts where you want to describe an entrance that is currently in use or being engaged with actively.
Example: "The active entrance to the building was bustling with people during the morning rush hour."
Alternatives: "engaged entry" or "dynamic entrance".
The number of traps per sett varied dependent on the number of active entrances and runs present, and was determined by an experienced surveyor.
Inhibition mechanism was assessed as being due to occlusion of the active site entrance by means of the NCs.
d-Trp is anchored at the edge of the CA II active site entrance, strongly interacting with amino acid residues Asp130, Phe131 and Gly132 as well as with a loop of a second symmetry related protein molecule from the asymmetric unit, by means of hydrogen bonds and several weak van der Waals interactions involving Glu234, Gly235, Glu236 and Glu238.
Therefore, the addition of an ion pair across the active site entrance was not detrimental to cyclosarin binding.
For each structure, the active site entrance forms a bottleneck that was used to delimit the volume of the gorge in the calculations.
Only residues on the plane opposite to the active site entrance were considered.
These include for example loop motions or the opening of lids which gate the active site entrance.
This in turn opens space for a different rotamer of Phe351, which renders the whole active site entrance loop more ordered than the wild-type structures.
In this position, the nicotinamide ring is located above the keto group of the substrates, and their aromatic rings point toward the active site entrance.
The binding of dUMP has an effect on the loop 100 127, causing it to move away from the center of the active site entrance and thus widening the latter.
