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

. 2021 May 5;8(13):2004685. doi: 10.1002/advs.202004685

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

© 2021 The Authors. Advanced Science published by Wiley‐VCH GmbH

This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

PMC Copyright notice

Structural features of type VI‐B CRISPR‐Cas effectors. All PyMOL figures were generated using the available structures of Bergeyella zoohelcum Cas13b (BzCas13b)‐crRNA binary complex (PDB ID: 6AAY) and Prevotella buccae Cas13b (PbuCas13b)‐crRNA binary complex (PDB ID: 6DTD). A,B) Top: linear domain organization of BzCas13b (A) and PbuCas13b (B) with the HEPN nuclease active site residues annotated. All figures use the same color code. Bottom: cartoon and surface representations of the overall structure of the BzCas13b‐crRNA binary complex (A) and PbuCas13b‐crRNA binary complex (B). Domains are colored according to the linear domain organization diagram and crRNA is colored red. C,D) Left: diagram of the BzCas13b‐crRNA (C) and PbuCas13b‐crRNA (D) secondary structure. Because the focus of the diagram is structure and sequence of the repeat region, spacer nucleotides were omitted and spacer region is represented by a gray line. Subregions of the repeat region are annotated, Watson–Crick base pairs are denoted with black lines, whereas non‐Watson–Crick base pairing is denoted with a black dot. Right: 3D structure of the crRNA repeat region from the BzCas13b‐crRNA binary complex (C) and PbuCas13b‐crRNA binary complex (D). Nucleotides belonging to repeat region are colored and annotated according to the diagram on the left, whereas spacer nucleotides were entirely omitted. E) Close‐up view of the opening on BzCas13b leading into the positively charged central cavity. The surface representation was set to solvent‐accessible mode for clarity and dimensions of the opening are given for comparison with the two openings on PbuCas13b. F) Top: close‐up view of the larger opening on PbuCas13b leading into the positively charged central cavity. Bottom: close‐up view of the smaller opening on BzCas13b leading into the positively charged central cavity. The surface representation was set to solvent‐accessible mode for clarity and dimensions of the openings are given for comparison with the opening on BzCas13b.