 |
PDBsum entry 1vcc
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Crystal structure of the amino-Terminal fragment of vaccinia virus DNA topoisomerase i at 1.6 a resolution.
|
|
|
Authors
|
|
A.Sharma,
R.Hanai,
A.Mondragón.
|
|
|
Ref.
|
|
Structure, 1994,
2,
767-777.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
BACKGROUND: Vaccinia virus, a cytoplasmically-replicating poxvirus, encodes a
type I DNA topoisomerase that is biochemically similar to eukaryotic-like DNA
topoisomerases I, and which has been widely studied as a model topoisomerase. It
is the smallest topoisomerase known and is unusual in that it is resistant to
the potent chemotherapeutic agent camptothecin. RESULTS: The crystal structure
of a 9 kDa amino-terminal fragment of vaccinia virus DNA topoisomerase I has
been determined at 1.6 A resolution. The fragment forms a five-stranded,
antiparallel beta-sheet with two short alpha-helices and connecting loops.
Residues that are conserved between all eukaryotic-like type I topoisomerases
are not clustered in particular regions of the structure. CONCLUSIONS: This is
the first atomic structure of any region of a eukaryotic-like DNA topoisomerase
I. It has provided insights into the structural bases of the phenotypes of some
single-site mutants of the intact topoisomerase. The structure has enabled us to
study the interactions within a well-folded protein fragment and the
camptothecin resistance of the viral topoisomerase.
|
|
|
|
|
|
|
|
Figure 2.
Figure 2. Electron density maps of vaccinia virus DNA
topoisomerase I. (a) The original MIRAS map to 2.8 å used
for tracing the amino-terminal fragment. The map is contoured at
1.0 σ. (b) 2F[o]– F[c] map at 1.6 å resolution of the
cryo-cooled protein model, contoured at 1.2σ. Figure 2.
Electron density maps of vaccinia virus DNA topoisomerase I. (a)
The original MIRAS map to 2.8 å used for tracing the
amino-terminal fragment. The map is contoured at 1.0 σ. (b)
2F[o]– F[c] map at 1.6 å resolution of the cryo-cooled
protein model, contoured at 1.2σ.
|
|
Figure 4.
Figure 4. Stereo view of the hydrophobic core in the amino
terminal fragment of vaccinia virus DNA topoisomerase I. The
ribbon diagram is shown in blue. All hydrophobic residues are
colored yellow, and hydrophilic residues in orange. The view is
looking down the core with the sheet on the right and the
helices on the left bottom. Figure 4. Stereo view of the
hydrophobic core in the amino terminal fragment of vaccinia
virus DNA topoisomerase I. The ribbon diagram is shown in blue.
All hydrophobic residues are colored yellow, and hydrophilic
residues in orange. The view is looking down the core with the
sheet on the right and the helices on the left bottom.
|
|
|
|
|
|
The above figures are
reprinted
by permission from Cell Press:
Structure
(1994,
2,
767-777)
copyright 1994.
|
|
|
|
|
|
|
