Referee 2's review:

In my first review, I said that I thought this work was interesting and provocative but that more details regarding the methodology would be of interest to non-experts. I also thought that structural models should be shown to better justify the claim of a "demonstration." The authors have addressed both of these suggestions.

I still think the work is better described as stimulating and provocative than as a definitive proof of either the proposed lateral gene transfer or the "hypothesis" that the convex surface might be the site of protein binding. Also, the iterations of constrained energy minimization used in the structural modeling do not represent a very thorough conformational search. However, I don't think the authors over-sell their results, and this interesting work deserves publication. It may well stimulate future studies to test the interesting ideas proposed here.

Some additional effort should be made to correct the spelling and English errors that remain, e.g., "compartimentalized" on page 11 and "unable" in place of "enable" on page 15.

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N.B. These are the comments made by the referee when reviewing an earlier version of this paper. Prior to publication the manuscript has been revised in light of these comments and to address other editorial requirements.