By slowly opening a clamp placed on the cannula, Starling increased the rate of blood flow from the reservoir into the right atrium.
While the recently determined structures show how the clamp is held in the open state by the clamp loader, they do not address whether the clamp loader actively opens the clamp or simply traps a transiently open state.
(A) Crystal structure of the T4 clamp loader, bound to a primer-template junction and an open clamp (Kelch et al., 2011).
Thus, these residues, which we show take part in the binding of human PCNA to DNA, may play a role in clamp loading by guiding DNA through the open clamp and into the clamp loader to form a tight complex.
A coarse-grained elastic model was also built; its strong correspondence to the all-atom MD simulations of PCNA suggests that the behavior of the open clamp is primarily due to elastic deformation governed by the topology of the clamp domains.
The Mazzoca group [3, 7] described the open clamp technique with a semitendinosus tendon which, despite using an anatomic collarbone implementation, only uses a single point of traction on the coracoid.
The T-segment is then passed through a transient break in the G-segment (opened by the N-terminal ParC (GyrA) domains), the DNA is resealed and the T-segment released through a protein gate prior to resetting of the enzyme to the open clamp form.
The T-segment is then passed through a transient break in the G-segment opened by the breakage-reunion domains, the DNA is resealed and the T-segment released through a protein gate, the C-gate, prior to resetting of the enzyme to the open clamp form.
The recent structures of the T4 clamp loader bound to an open clamp and primer template DNA indicate how loaders open a clamp [ 60].
The right-handed spiral of the open clamp roughly matches the helical symmetry of DNA, with the clamp tracking along the minor groove of the DNA duplex.
