PDBsum entry 6is9

DNA binding protein

PDB id: 6is9

Contents

Protein chains

180 a.a.

168 a.a.

Waters ×222

PDB id:

6is9

Name:

DNA binding protein

Title:

Crystal structure of zmmoc1

Structure:

Monokaryotic chloroplast 1. Chain: a, b. Fragment: ruvc domain. Engineered: yes

Source:

Zea mays. Maize. Organism_taxid: 4577. Gene: moc1. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

1.86Å R-factor: 0.176 R-free: 0.209

Authors:

Z.Lin,H.Lin,D.Zhang,C.Yuan

Key ref:

H.Lin et al. (2019). Structural basis of sequence-specific Holliday junction cleavage by MOC1. Nat Chem Biol, 15, 1241-1248. PubMed id: 31611704 DOI: 10.1038/s41589-019-0377-4

Date:

15-Nov-18 Release date: 23-Oct-19

Protein chain

B4FCI7  (B4FCI7_MAIZE) -  Holliday junction resolvase MOC1, chloroplastic from Zea mays

Seq: 280 a.a.

Struc: 180 a.a.

Protein chain

B4FCI7  (B4FCI7_MAIZE) -  Holliday junction resolvase MOC1, chloroplastic from Zea mays

Seq: 280 a.a.

Struc: 168 a.a.*

* PDB and UniProt seqs differ at 6 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, B: E.C.?

DOI no: 10.1038/s41589-019-0377-4

Nat Chem Biol 15:1241-1248 (2019)

PubMed id: 31611704

Structural basis of sequence-specific Holliday junction cleavage by MOC1.

H.Lin, D.Zhang, K.Zuo, C.Yuan, J.Li, M.Huang, Z.Lin.

ABSTRACT

The Holliday junction (HJ) is a key intermediate during homologous recombination and DNA double-strand break repair. Timely HJ resolution by resolvases is critical for maintaining genome stability. The mechanisms underlying sequence-specific substrate recognition and cleavage by resolvases remain elusive. The monokaryotic chloroplast 1 protein (MOC1) specifically cleaves four-way DNA junctions in a sequence-specific manner. Here, we report the crystal structures of MOC1 from Zea mays, alone or bound to HJ DNA. MOC1 uses a unique β-hairpin to embrace the DNA junction. A base-recognition motif specifically interacts with the junction center, inducing base flipping and pseudobase-pair formation at the strand-exchanging points. Structures of MOC1 bound to HJ and different metal ions support a two-metal ion catalysis mechanism. Further molecular dynamics simulations and biochemical analyses reveal a communication between specific substrate recognition and metal ion-dependent catalysis. Our study thus provides a mechanism for how a resolvase turns substrate specificity into catalytic efficiency.