RT @NatureSMB: Here, @JoshCofsky, @doudna_lab, and colleagues, use #CryoEM and biochemical analysis to investigate how the #CRISPR associat….

Have you ever wondered how A-form and B-form nucleic acid helices might interact with each other during the expansion of a Cas9-bound R-loop? Check out our crystal structure of an interhelical stack in @PLOSONE ! #stacked.🙏 @doudna_lab @gavinjknott +CLG.

Join millions who have switched to Grok.

"A tweak and a peek"! Our Cas9 paper is now out in @NatureSMB (. Thanks also to Sinan + Russell for the News & Views article (, which nailed it with the title and the beautiful explanations :).🙏@doudna_lab @gavinjknott @NogalesLab.

RT @jpkbravo: 1. I am thrilled to share the accepted version of our Cas9 mismatch manuscript, now in @Nature! Here’s a (not-so) brief outli….

The first crystal structure I solved myself, no thanks to some pesky diffraction anisotropy! With crucial help from @gavinjknott, Christine Gee, and @doudna_lab, of course. If you don't care about nucleic acid structure, just check out the sexy lattice architecture in Fig. 1 😍

RT @MartinPacesa: Keeping the ball rolling with my next manuscript from the @MartinJinek lab! We solved several .structures of intermediary….

RT @davidwtaylorjr: (1/2) Cas9 can cut off-targets. We used kinetics-guided structural studies of Cas9 bound to different mismatches and re….

Thanks to @berkeleyMCB and all my wonderful co-authors (Kasia Soczek, @gavinjknott, @NogalesLab, @doudna_lab) for making these discoveries possible and teaching me a thing or two about structural biology 🧬 (8/8).

The speed with which Cas9 performs these bending actions may determine how fast it can find its target. Also, Cas9 may interact differently with pre-bent DNA sequences (such as those wrapped around histones). Both important considerations for genome editing efficiency! (7/8)

My favorite part: we also revived some old-school solution biochemistry experiments (cyclization efficiency and permanganate reactivity measurements) to make sure the EM data weren't fooling us. (6/8)

Structural modeling suggests that Cas9 may engage a twisting motion between its two lobes to manipulate the DNA in this way. (5/8)

Using cryo-EM, we caught the complex in two different states—one in which the DNA is linear (a putative DNA scanning state), and one in which the DNA is bent/twisted in a way that exposes nucleobases to be checked for complementarity to the guide RNA. (4/8)

We used an old chemical trick from the Verdine Lab to staple Cas9 to a piece of DNA that has a PAM but is not complementary to the guide RNA, holding the interrogation complex together long enough for us to do experiments on it. (3/8)

A key step in RNA-guided target search is breaking open DNA base pairs next to the PAM. It'd be great to see what that process looks like, but it's difficult to observe because it occurs so quickly (estimated lifetime <30 ms). (2/8).

New pre-print! While #CRISPR-Cas9 searches through the genome, how does it actually "read" DNA sequence information, which is normally hidden within the double helix? We determined structures of Cas9 in the act of DNA interrogation to find out! Thread below 👇 (1/8).