Biomedical Engineering Reference
In-Depth Information
Figure 10.20
A superposition of 64 MD snapshots of a run to compute the structure
of the DnaK-J complex based on PRE distance restraints. DnaK NBD
is yellow and the DnaJ J-domain is white. Nota bene: the NMR
relaxation data show that DnaJ(1-70) is dynamically tethered to DnaK
with S
2
5 0.37, so each of the J-positions is a possible dynamic
average. Adapted from ref. 32.
In summary, we discovered a novel molecular interaction mode in which the
two non-covalently-bound proteins retain considerable relative mobility
through a dynamic interface. In this case, the interaction occurs likely through
electrostatic interactions of the floppy side-chains of positive Lys and Arg
residues on DnaJ with negative Glu and Asp residues on DnaK. We call the
phenomenon 'tethered binding'. Tethered binding is not to be confused with
transient or weak binding. In tethered binding, the dynamics occur when the
molecule is bound (saturated binding site)—not unlike a floppy C-terminal tail
on a protein. In transient and weak binding the dynamics occurs in the binding
process itself, and the saturated complex by itself is not dynamic.
