PDBsum entry 6dd5

Hydrolase

PDB id: 6dd5

Contents

Protein chains

652 a.a.

Ligands

GLC-GLC ×2

GOL ×2

SO4 ×17

PDB id:

6dd5

Name:

Hydrolase

Title:

Crystal structure of the cas6 domain of marinomonas mediterranea mmb-1 cas6-rt-cas1 fusion protein

Structure:

Mmb-1 cas6 fused to maltose binding protein,crispr- associated endonuclease cas1. Chain: a, b. Synonym: mbp,mmbp,maltodextrin-binding protein. Engineered: yes

Source:

Escherichia coli o157:h7, marinomonas mediterranea mmb-1. Organism_taxid: 83334, 717774. Strain: atcc 700492 / jcm 21426 / nbrc 103028 / mmb-1. Gene: male, z5632, ecs5017, cas1, marme_0669. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.85Å R-factor: 0.189 R-free: 0.225

Authors:

J.L.Stamos,G.Mohr,S.Silas,K.S.Makarova,L.M.Markham,J.Yao,P.Lucas- Elio,A.Sanchez-Amat,A.Z.Fire,E.V.Koonin,A.M.Lambowitz

Key ref:

G.Mohr et al. (2018). A Reverse Transcriptase-Cas1 Fusion Protein Contains a Cas6 Domain Required for Both CRISPR RNA Biogenesis and RNA Spacer Acquisition. Mol Cell, 72, 700. PubMed id: 30344094 DOI: 10.1016/j.molcel.2018.09.013

Date:

09-May-18 Release date: 17-Oct-18

Protein chains

F2K1V9  (F2K1V9_MARM1) -  CRISPR-associated endonuclease Cas1 from Marinomonas mediterranea (strain ATCC 700492 / JCM 21426 / NBRC 103028 / MMB-1)

Seq: 957 a.a.

Struc: 652 a.a.*

Protein chains

P0AEX9  (MALE_ECOLI) -  Maltose/maltodextrin-binding periplasmic protein from Escherichia coli (strain K12)

Seq: 396 a.a.

Struc: 652 a.a.*

* PDB and UniProt seqs differ at 8 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.-.-

DOI no: 10.1016/j.molcel.2018.09.013

Mol Cell 72:700 (2018)

PubMed id: 30344094

A Reverse Transcriptase-Cas1 Fusion Protein Contains a Cas6 Domain Required for Both CRISPR RNA Biogenesis and RNA Spacer Acquisition.

G.Mohr, S.Silas, J.L.Stamos, K.S.Makarova, L.M.Markham, J.Yao, P.Lucas-Elío, A.Sanchez-Amat, A.Z.Fire, E.V.Koonin, A.M.Lambowitz.

ABSTRACT

Prokaryotic CRISPR-Cas systems provide adaptive immunity by integrating portions of foreign nucleic acids (spacers) into genomic CRISPR arrays. Cas6 proteins then process CRISPR array transcripts into spacer-derived RNAs (CRISPR RNAs; crRNAs) that target Cas nucleases to matching invaders. We find that a Marinomonas mediterranea fusion protein combines three enzymatic domains (Cas6, reverse transcriptase [RT], and Cas1), which function in both crRNA biogenesis and spacer acquisition from RNA and DNA. We report a crystal structure of this divergent Cas6, identify amino acids required for Cas6 activity, show that the Cas6 domain is required for RT activity and RNA spacer acquisition, and demonstrate that CRISPR-repeat binding to Cas6 regulates RT activity. Co-evolution of putative interacting surfaces suggests a specific structural interaction between the Cas6 and RT domains, and phylogenetic analysis reveals repeated, stable association of free-standing Cas6s with CRISPR RTs in multiple microbial lineages, indicating that a functional interaction between these proteins preceded evolution of the fusion.