Architecture of the Bacterial Flagellar Distal Rod and Hook of Salmonella
Round 1
Reviewer 1 Report
The work titled Architecture of the bacterial distal rod and hook of Salmonella shows the molecular basis of the different mechanical properties of the distal rod protein FlgG and the hook protein FlgE. This study shoes an important finding that solves the fundamental question about the mechanical properties of these highly similar proteins; the rigidity of the rod and the flexibility of the hook.
In this reviewer's opinion the work makes a solid contribution and is suitable for publication.
I have a few specific comments mostly regarding changes in the use of english.
1- Line18 include "composed" after molecular complex.
2- Line 20 "rods" should be "rod". Describe what the authors refer as "minor components" Hook Associated Proteins perhaps.
3-Line 21 Change "property" for "properties"
4- Line 22 Delete "both"
5-Line 24 Delete "from each other"
6- Line 25 "curved tube with a high bending.." delete a
7- Line 26 Delete "previous"
8- Line 27 Insert "previously" after obtained
9- Line 33 Insert "a" after "rotating"
10- Line 38 Delete "an" and describe "the few minor components"
11- Line 39 Include the unit of measure "15 nm??"
12- line 42 The term "smoothly" is inadequate, could be omitted. Delete "its" after "filament in"
13- line 45 Insert "that" after "shaft" and change "penetrating" for "penetrates"
14- Line 51 "The inner most delete "most"
15- Line 65 Insert "of these structures" after "properties"
16- Line 75 Change "Recent" for "Recently the"
17- Line 79 Insert "would be" delete "is"
18- Line 99 Move "more" after "resembles"
19- Line 157 Change "FlgG20 is" for "are"
20- Line 160 Insert "fits" before "nicely". Delete "fit"
21- Line 218 Delete "In"
22- Line 237 Insert "are" after ...distance and...
23- Line 239 Delete "also" at the begining of the line
24- Line 240 Insert "this difference" after ....the distal rod...
25- Line 276 Should read " The poly-rod mutations"
26- Line 279 insert "a" after ....map of...
27- Line 280 Insert "the" after ...suggest that...
Author Response
Thank you very much for your favorable comment. We appreciate the correction of our manuscript. The manuscript was revised according to your suggestion. All corrections are highlighted in red in the manuscript.
I have a few specific comments mostly regarding changes in the use of english.
1- Line18 include "composed" after molecular complex.
2- Line 20 "rods" should be "rod". Describe what the authors refer as "minor components" Hook Associated Proteins perhaps.
3-Line 21 Change "property" for "properties"
4- Line 22 Delete "both"
5-Line 24 Delete "from each other"
6- Line 25 "curved tube with a high bending.." delete a
7- Line 26 Delete "previous"
8- Line 27 Insert "previously" after obtained
9- Line 33 Insert "a" after "rotating"
10- Line 38 Delete "an" and describe "the few minor components"
11- Line 39 Include the unit of measure "15 nm??"
12- line 42 The term "smoothly" is inadequate, could be omitted. Delete "its" after "filament in"
13- line 45 Insert "that" after "shaft" and change "penetrating" for "penetrates"
14- Line 51 "The inner most delete "most"
15- Line 65 Insert "of these structures" after "properties"
16- Line 75 Change "Recent" for "Recently the"
17- Line 79 Insert "would be" delete "is"
18- Line 99 Move "more" after "resembles"
19- Line 157 Change "FlgG20 is" for "are"
20- Line 160 Insert "fits" before "nicely". Delete "fit"
21- Line 218 Delete "In"
22- Line 237 Insert "are" after ...distance and...
23- Line 239 Delete "also" at the begining of the line
24- Line 240 Insert "this difference" after ....the distal rod...
25- Line 276 Should read " The poly-rod mutations"
26- Line 279 insert "a" after ....map of...
27- Line 280 Insert "the" after ...suggest that...
R: Corrected.
Reviewer 2 Report
The study by Saijo-Hamano and coworkers aims at explaining structural differences of rod and hook by a combination of X-ray diffraction experiments and cryo-EM. They show that despite a high sequence conservation, rod and hook proteins FlgG and FlgE have undergone slight modifications that allow to account for the individual mechanical needs. More precisely they show that the L-stretch of FlgG contributes to reduce flexibility in the rod, while less contacts with the D1 domain allow more flexibility within FlgE. I generally favor publication of the current manuscript while outlining some minor issues below.
All figures would benefit from labeling the different domains of FlgG and FlgE as this allows the reader to easier follow the outlined domain contacts. In addition to this, I would appreciate figures of the models docked in the cryo-EM map (especially the contact area between D1 and the L-stretch) either in figure 2 and 3 or as supplemental figures.
Line 39: the µ is missing or not properly displayed in my version.
Table 1: The high value for I/sI in the outer shell indicates that the authors truncated the data rather conservatively. According to current procedures, CC ½ is a better criterion to judge the resolution of a dataset than Rmerge which would have possibly allowed to extend the resolution of the data.
The t is missing in “Map correlation coefficient”.
Line 173: I might have missed it but the program used for figure generation is neither given in the figure text nor in the method section.
Line 218: Change to: Consistent with this, …
Author Response
Thank you very much for your favorable comment. We revised the manuscript in accordance with your suggestion. Our responses to the reviewer comments are listed below. All corrections are highlighted in red in the manuscript.
All figures would benefit from labeling the different domains of FlgG and FlgE as this allows the reader to easier follow the outlined domain contacts. In addition to this, I would appreciate figures of the models docked in the cryo-EM map (especially the contact area between D1 and the L-stretch) either in figure 2 and 3 or as supplemental figures.
R: The domains were labeled in the figures. We added a new supplemental figure (Figure S2) that diplays the rod model in the cryo-EM map.
Table 1: The high value for I/sI in the outer shell indicates that the authors truncated the data rather conservatively. According to current procedures, CC ½ is a better criterion to judge the resolution of a dataset than Rmerge which would have possibly allowed to extend the resolution of the data.
R: This was simply because of the limitation of the experimental setting. The best crystal diffracted more than 2.0 Å, but we could not change the camera length at that time due to some reason.
Line 39: the μ is missing or not properly displayed in my version.
Table 1: The t is missing in “Map correlation coefficient”.
Line 218: Change to: Consistent with this, …
R: Corrected.
Line 173: I might have missed it but the program used for figure generation is neither given in the figure text nor in the method section.
R: We wrote the name of the program in each figure legend.
