5YBB

Structural basis underlying complex assembly andconformational transition of the type I R-M system

Summary for 5YBB

• Entry DOI: 10.2210/pdb5ybb/pdb
• Descriptor: Type I restriction-modification system methyltransferase subunit, Restriction endonuclease S subunits, DNA, ... (5 entities in total)
• Functional Keywords: protein complex typei rm system mtase ecoki, dna binding protein-dna complex, dna binding protein/dna
• Biological source: Caldanaerobacter subterraneus subsp. tengcongensis (strain DSM 15242 / JCM 11007 / NBRC 100824 / MB4) (Thermoanaerobacter tengcongensis); More
• Total number of polymer chains: 8
• Total formula weight: 338012.02

Authors

Liu, Y.P.,Tang, Q.,Zhang, J.Z.,Tian, L.F.,Gao, P.,Yan, X.X. (deposition date: 2017-09-04, release date: 2017-11-29, Last modification date: 2024-11-06)

Primary citation

Liu, Y.P.,Tang, Q.,Zhang, J.Z.,Tian, L.F.,Gao, P.,Yan, X.X.
Structural basis underlying complex assembly and conformational transition of the type I R-M system.
Proc. Natl. Acad. Sci. U.S.A., 114:11151-11156, 2017

PubMed Abstract: Type I restriction-modification (R-M) systems are multisubunit enzymes with separate DNA-recognition (S), methylation (M), and restriction (R) subunits. Despite extensive studies spanning five decades, the detailed molecular mechanisms underlying subunit assembly and conformational transition are still unclear due to the lack of high-resolution structural information. Here, we report the atomic structure of a type I MTase complex (2M+1S) bound to DNA and cofactor S-adenosyl methionine in the "open" form. The intermolecular interactions between M and S subunits are mediated by a four-helix bundle motif, which also determines the specificity of the interaction. Structural comparison between open and previously reported low-resolution "closed" structures identifies the huge conformational changes within the MTase complex. Furthermore, biochemical results show that R subunits prefer to load onto the closed form MTase. Based on our results, we proposed an updated model for the complex assembly. The work reported here provides guidelines for future applications in molecular biology.

PubMed: 28973912
DOI: 10.1073/pnas.1711754114

Experimental method

X-RAY DIFFRACTION (3.2 Å)