Our previous gel filtration of Pac13 suggested a monomer.1 Analysis of the crystal structure was inconclusive.1, 2 Therefore based on the gel filtration analyses we concluded this protein to be a monomer in solution.
Thanks to the letter of Professor Rundong Zhang4 we revisited these experiments. Although a recent re‐run of the gel filtration of a sample of Pac13 that we had in hand was more ambiguous, it remained more consistent with a monomer (Figure 1 of this Corrigendum). We then examined the protein sample using the more definitive technique of multi‐angle light scattering (MALS), an analytical technique that we had not used in our initial study. These MALS analyses indicate the protein to have a MW of 27.3 KDa (Table 1 of this Corrigendum).
Figure 1.
Repeated and annotated gel filtration of a sample of Pac13. a) Raw trace data for Pac13. b) Raw trace data calibration standards. Pac13 was expressed with a His8 tag, and following TEV cleavage, an additional 3 amino acid residues remain. Calculated MW: 14096Da (monomer), 28192 Da (dimer).1, 3
Table 1.
MALS data.
|
Hydrodynamic radius (Q) moments [nm] | |
|---|---|
|
Rh(Q)z |
3.048 (±4.977 %) |
|
Rh(Q)(avg) |
2.688 (±1.665 %) |
|
Masses | |
|---|---|
|
Calculated Mass [μg] |
56.81 |
|
Molar mass moments [g mol−1] | |
|---|---|
|
Mn |
2.726×104 (±0.629 %) |
|
Mp |
2.709×104 (±0.606 %) |
|
Mw |
2.726×104 (±0.630 %) |
|
rms radius moments [nm] | |
|---|---|
|
Rz |
12.4 (±17.0%) |
From MALS analysis, we conclude that Pac13 is indeed dimeric. References in the original work to Pac13 being a monomer should thus be removed, along with the term “monomeric” in the original title. The other results, discussion, and conclusions in the Communication are not altered by the revised conclusion of the oligomeric species.
We thank Hannes Ludewig and Jag Dhaliwal (University of St Andrews), and Audrey LeBas and Gemma Harris (Research Complex at Harwell, Rutherford Laboratory) for their roles in producing further protein and carrying out gel filtration and MALS analysis.
References
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