 |
PDBsum entry 3uj3
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Recombination
|
PDB id
|
|
|
|
3uj3
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Crystal structure of an intermediate of rotating dimers within the synaptic tetramer of the g-Segment invertase.
|
|
|
Authors
|
|
C.J.Ritacco,
S.Kamtekar,
J.Wang,
T.A.Steitz.
|
|
|
Ref.
|
|
Nucleic Acids Res, 2013,
41,
2673-2682.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
