An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Processing flowchart for Data S1. Protomer maps from masked classification are unsharpened, with the two other protomers removed for clarity. All maps are contoured at 8 σ.