. Author manuscript; available in PMC: 2021 Sep 21.
Published in final edited form as: J Mol Biol. 2016 Jan 11;428(10 Pt A):2011–24. doi: 10.1016/j.jmb.2016.01.002
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).