We hypothesized that the role of K279 is to bind the phosphate backbone of the acceptor stem of misacylated tRNAPro and position it in the editing active site.
On the basis of previous experimental, substrate docking, and MD simulation results, we hypothesized that the role of the conserved lysine may be to anchor the phosphate backbone of the acceptor stem of misacylated tRNAPro and position it into the editing active site.
RMSD values for the EF loop backbone of stem(0) and stem- 0) were 0.05/0.10 nm and 0.13/0.9 nm, restem- 0ely (Supplementary Fig. 4).
In the model, the trajectory of the phosphate backbone of the A-form stem structure in the tetraloop substrate approaches close enough to form electrostatic interactions with K110, K111, and K113.
To examine if binding of the backbone of the tRNA acceptor stem to INS is favored by the lysine at position 279, the free energy of binding of 5′-CCA-Ala to the editing domain was compared between WT INS and the ProRS mutants.
This finding suggests that the presence of a positively charged or neutral residue at position 303 of Ec ProRS enhances the positive charge density at position 279, which is likely to increase the binding affinity of K279 for the backbone of the tRNA acceptor stem.
Cryopreservation of hematopoietic stem cells (HSC) is the backbone of clinical stem cell transplantation (SCT), and this technique is an essential part of autologous SCT [1], cord blood transplantation (CBT) and in many cases, allogeneic SCT [2], particularly when the donor is elderly and the stem cells are not readily available.
First, 16 residues in Domains 1 and 3 of the protein form hydrogen bonds and ion pairs primarily with the helical backbone of the acceptor and T-stems of aa-tRNA.
Recent reinvestigation of these transferases demonstrated that are rather related to the elongation of the backbone of xylan in stems (Alan Marchant, personnel communication).
A moderate effect of the yArg481His substitution is in agreement with the observation that the Arg versus His change is electrostatically conservative, the equivalent Arg in GidA from C. tepidum being predicted to participate in a positively charged pocket, formed by several Arg, Lys, and His residues, that binds the phosphates of the D-stem backbone of the incoming tRNA.
