EMD-1893
EcoKI Type I DNA restriction-modification enzyme complex in closed state with bound 75bp cognate DNA fragment. 3D reconstruction by single particle analysis from negative stain EM.
EMD-1893
Single-particle20.0 Å
Deposition: 06/04/2011Map released: 15/02/2012
Last modified: 24/10/2012
Sample Organism:
Escherichia coli,
synthetic construct
Sample: EcoKI R2 M2 S1 complex with 75 bp cognate dsDNA fragment
Deposition Authors: Kennaway CK, Taylor JE
,
Song CF,
Potrzebowski W ,
White JH,
Swiderska A,
Obarska-Kosinska A,
Callow P,
Cooper LP,
Roberts GA,
Bujnicki JM,
Trinick J,
Kneale GG,
Dryden DTF
Sample: EcoKI R2 M2 S1 complex with 75 bp cognate dsDNA fragment
Deposition Authors: Kennaway CK, Taylor JE
,
Song CF,
Potrzebowski W ,
White JH,
Swiderska A,
Obarska-Kosinska A,
Callow P,
Cooper LP,
Roberts GA,
Bujnicki JM,
Trinick J,
Kneale GG,
Dryden DTF
Structure and operation of the DNA-translocating type I DNA restriction enzymes.
Kennaway CK,
Taylor JE ,
Song CF,
Potrzebowski W ,
Nicholson W ,
White JH,
Swiderska A,
Obarska-Kosinska A,
Callow P,
Cooper LP,
Roberts GA,
Artero JB,
Bujnicki JM,
Trinick J,
Kneale GG,
Dryden DT
(2012) Genes Dev. , 26 , 92 - 104
,
Song CF,
Potrzebowski W ,
Nicholson W ,
White JH,
Swiderska A,
Obarska-Kosinska A,
Callow P,
Cooper LP,
Roberts GA,
Artero JB,
Bujnicki JM,
Trinick J,
Kneale GG,
Dryden DT
(2012) Genes Dev. , 26 , 92 - 104
Abstract:
Type I DNA restriction/modification (RM) enzymes are molecular machines found in the majority of bacterial species. Their early discovery paved the way for the development of genetic engineering. They control (restrict) the influx of foreign DNA via horizontal gene transfer into the bacterium while maintaining sequence-specific methylation (modification) of host DNA. The endonuclease reaction of these enzymes on unmethylated DNA is preceded by bidirectional translocation of thousands of base pairs of DNA toward the enzyme. We present the structures of two type I RM enzymes, EcoKI and EcoR124I, derived using electron microscopy (EM), small-angle scattering (neutron and X-ray), and detailed molecular modeling. DNA binding triggers a large contraction of the open form of the enzyme to a compact form. The path followed by DNA through the complexes is revealed by using a DNA mimic anti-restriction protein. The structures reveal an evolutionary link between type I RM enzymes and type II RM enzymes.
Type I DNA restriction/modification (RM) enzymes are molecular machines found in the majority of bacterial species. Their early discovery paved the way for the development of genetic engineering. They control (restrict) the influx of foreign DNA via horizontal gene transfer into the bacterium while maintaining sequence-specific methylation (modification) of host DNA. The endonuclease reaction of these enzymes on unmethylated DNA is preceded by bidirectional translocation of thousands of base pairs of DNA toward the enzyme. We present the structures of two type I RM enzymes, EcoKI and EcoR124I, derived using electron microscopy (EM), small-angle scattering (neutron and X-ray), and detailed molecular modeling. DNA binding triggers a large contraction of the open form of the enzyme to a compact form. The path followed by DNA through the complexes is revealed by using a DNA mimic anti-restriction protein. The structures reveal an evolutionary link between type I RM enzymes and type II RM enzymes.