7XN2

Crystal structure of CvkR, a novel MerR-type transcriptional regulator

Summary for 7XN2

• Entry DOI: 10.2210/pdb7xn2/pdb
• Descriptor: Alr3614 protein, ADENOSINE-5'-TRIPHOSPHATE, DI(HYDROXYETHYL)ETHER, ... (4 entities in total)
• Functional Keywords: merr-type transcriptional regulator, transcription
• Biological source: Nostoc sp. PCC 7120 = FACHB-418
• Total number of polymer chains: 1
• Total formula weight: 18361.56

Authors

Liang, Y.J.,Zhu, T.,Ma, H.L.,Lu, X.F.,Hess, W.R. (deposition date: 2022-04-27, release date: 2023-03-08, Last modification date: 2024-05-29)

Primary citation

Ziemann, M.,Reimann, V.,Liang, Y.,Shi, Y.,Ma, H.,Xie, Y.,Li, H.,Zhu, T.,Lu, X.,Hess, W.R.
CvkR is a MerR-type transcriptional repressor of class 2 type V-K CRISPR-associated transposase systems.
Nat Commun, 14:924-924, 2023

PubMed Abstract: Certain CRISPR-Cas elements integrate into Tn7-like transposons, forming CRISPR-associated transposon (CAST) systems. How the activity of these systems is controlled in situ has remained largely unknown. Here we characterize the MerR-type transcriptional regulator Alr3614 that is encoded by one of the CAST (AnCAST) system genes in the genome of cyanobacterium Anabaena sp. PCC 7120. We identify a number of Alr3614 homologs across cyanobacteria and suggest naming these regulators CvkR for Cas V-K repressors. Alr3614/CvkR is translated from leaderless mRNA and represses the AnCAST core modules cas12k and tnsB directly, and indirectly the abundance of the tracr-CRISPR RNA. We identify a widely conserved CvkR binding motif 5'-AnnACATnATGTnnT-3'. Crystal structure of CvkR at 1.6 Å resolution reveals that it comprises distinct dimerization and potential effector-binding domains and that it assembles into a homodimer, representing a discrete structural subfamily of MerR regulators. CvkR repressors are at the core of a widely conserved regulatory mechanism that controls type V-K CAST systems.

PubMed: 36801863
DOI: 10.1038/s41467-023-36542-9

Experimental method

X-RAY DIFFRACTION (1.6 Å)