Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

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.

View full-text article in PMC

. 2019 Jan 3;47(6):3158–3170. doi: 10.1093/nar/gky1311

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Published by Oxford University Press on behalf of Nucleic Acids Research 2019.

This work is written by (a) US Government employee(s) and is in the public domain in the US.

PMC Copyright notice

Figure 1. — Secondary and tertiary structure of full-length SAM-I riboswitch (with sequence) in SAM-bound transcription OFF state and SAM-free transcription ON state. (A) Sequence-aligned secondary structure and (B) tertiary structure of the transcription OFF state of SAM-I riboswitch in the presence of metabolite, SAM (yellow pentagon) surrounded by explicit magnesium ions (purple). Different secondary structural segments are defined sequence-wise. Note the partially overlapped aptamer and EP (EP) domains. (C) Sequence-aligned secondary structure and (D) tertiary structures of the transcription ON state surrounded by explicit magnesium (purple) ions. Four characteristic segments, important for switching, are designated with distinct colors: Red: switching strand; green: terminator helix in the EP domain; black: flexible aptamer; gray: more stable aptamer. In the transcription OFF state the flexible aptamer owns the red switching strand. In the transcription ON state green terminator sequesters the red switching strand.