PDBsum entry 3uj3

Recombination

PDB id: 3uj3

Contents

Protein chain

124 a.a.

PDB id:

3uj3

Name:

Recombination

Title:

Crystal structure of the synaptic tetramer of the g-segment invertase (gin)

Structure:

DNA-invertase. Chain: x. Engineered: yes. Mutation: yes

Source:

Enterobacteria phage mu. Organism_taxid: 10677. Gene: gin, 51. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

3.51Å R-factor: 0.259 R-free: 0.289

Authors:

C.J.Ritacco,J.Wang,S.Kamtekar,T.A.Steitz

Key ref:

C.J.Ritacco et al. (2013). Crystal structure of an intermediate of rotating dimers within the synaptic tetramer of the G-segment invertase. Nucleic Acids Res, 41, 2673-2682. PubMed id: 23275567

Date:

07-Nov-11 Release date: 05-Dec-12

Supersedes:

3plo

Protein chain

P03015  (GIN_BPMU) -  Serine recombinase gin from Escherichia phage Mu

Seq: 193 a.a.

Struc: 124 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class 2: E.C.3.1.22.- - ?????
• Enzyme class 3: E.C.6.5.1.- - ?????

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Nucleic Acids Res 41:2673-2682 (2013)

PubMed id: 23275567

Crystal structure of an intermediate of rotating dimers within the synaptic tetramer of the G-segment invertase.

C.J.Ritacco, S.Kamtekar, J.Wang, T.A.Steitz.

ABSTRACT

The serine family of site-specific DNA recombination enzymes accomplishes strand cleavage, exchange and religation using a synaptic protein tetramer. A double-strand break intermediate in which each protein subunit is covalently linked to the target DNA substrate ensures that the recombination event will not damage the DNA. The previous structure of a tetrameric synaptic complex of γδ resolvase linked to two cleaved DNA strands had suggested a rotational mechanism of recombination in which one dimer rotates 180° about the flat exchange interface for strand exchange. Here, we report the crystal structure of a synaptic tetramer of an unliganded activated mutant (M114V) of the G-segment invertase (Gin) in which one dimer half is rotated by 26° or 154° relative to the other dimer when compared with the dimers in the synaptic complex of γδ resolvase. Modeling shows that this rotational orientation of Gin is not compatible with its being able to bind uncleaved DNA, implying that this structure represents an intermediate in the process of strand exchange. Thus, our structure provides direct evidence for the proposed rotational mechanism of site-specific recombination.