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PDBsum entry 1of1
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Biochemical and structural characterization of (south)-Methanocarbathymidine that specifically inhibits growth of herpes simplex virus type 1 thymidine kinase-Transduced osteosarcoma cells.
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Authors
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P.Schelling,
M.T.Claus,
R.Johner,
V.E.Marquez,
G.E.Schulz,
L.Scapozza.
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Ref.
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J Biol Chem, 2004,
279,
32832-32838.
[DOI no: ]
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PubMed id
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Abstract
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Two analogs of the natural nucleoside dT featuring a pseudosugar with fixed
conformation in place of the deoxyribosyl residue (carbathymidine analogs) were
biochemically and structurally characterized for their acceptance by both human
cytosolic thymidine kinase isoenzyme 1 (hTK1) and herpes simplex virus type 1
thymidine kinase (HSV1 TK) and subsequently tested in cell proliferation assays.
3'-exo-Methanocarbathymidine ((South)-methanocarbathymidine (S)-MCT), which is a
substrate for HSV1 TK, specifically inhibited growth of HSV1 TK-transduced human
osteosarcoma cells with an IC(50) value in the range of 15 microM without
significant toxicity toward both hTK1-negative (TK(-)) and non-transduced cells.
2'-exo-Methanocarbathymidine ((North)-methanocarbathymidine (N)-MCT), which is a
weak substrate for hTK1 and a substantial one for HSV1 TK, induced a specific
growth inhibition in HSV1 TK-transfected cells comparable to that of (S)-MCT and
ganciclovir. A growth inhibition activity was also observed with (N)-MCT and
ganciclovir in non-transduced cells in a cell line-dependent manner, whereas
TK(-) cells were not affected. The presented 1.95-A crystal structure of the
complex (S)-MCT.HSV1 TK explains both the more favorable binding affinity and
catalytic turnover of (S)-MCT for HSV1 TK over the North analog. Additionally
the plasticity of the active site of the enzyme is addressed by comparing the
binding of (North)- and (South)-carbathymidine analogs. The presented study of
these two potent candidate prodrugs for HSV1 TK gene-directed enzyme prodrug
therapy suggests that (S)-MCT may be even safer to use than its North
counterpart (N)-MCT.
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Figure 1.
FIG. 1. Structures of (N)-MCT (A) and (S)-MCT (B).
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Figure 5.
FIG. 5. Stereoview of HSV1 TK structure in complex with
(S)-MCT. The conformation of the compound and the position of
the sulfate group are well defined by the electron density
contoured at 1.3  . The hydrogen bonding
patterns for the thymine moiety as well as for both 3'-OH and
5'-OH groups are the same as in the HSV1 TK·dT structure.
(S)-MCT and HSV1 TK carbon atoms are represented in orange and
black; nitrogen, oxygen, and sulfur atoms are in blue, red, and
yellow, respectively; and water molecules are represented as
green balls. H-bonds are depicted by dashed lines between donor
(D) and acceptor (A) and defined as follows: distance D--A,
2.8-3.2 Å; angle D-H--A, 140-180°.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2004,
279,
32832-32838)
copyright 2004.
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Secondary reference #1
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Title
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The three-Dimensional structure of thymidine kinase from herpes simplex virus type 1.
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Authors
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K.Wild,
T.Bohner,
A.Aubry,
G.Folkers,
G.E.Schulz.
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Ref.
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FEBS Lett, 1995,
368,
289-292.
[DOI no: ]
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PubMed id
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Figure 1.
Fig. 1. Sketch of the chain fold of thymidine kinase from Herpes
simplex virus type 1. To avoid crossovers the sketch is somewhat sim-
plified rendering some helix positions disputable. All ,B-strands (quad-
rangles) run towards the viewer, the orientations of the helices (circles)
are indicated by the arrows. Dashed lines denote chain segments that
are not yet modeled. The central residues of secondary structure ele-
ments bl, b2, b3, b4, b5, al, a, a3 a4, a5, a6, a7, a8, a9, al0, al 1, and
a12 are 52, 79, 159, 203, 326, 67, 87, 103, 131, 72, 190, 215, 239, 292,
314, 340, and 364, respectively.
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Figure 2.
Fig. 2. Stereo-view of the current a-backbone of dimeric thymidine kinase from Herpes simplex virus type 1 with numbering and the bound substrates
thymidine and ATP. The dashed lines indicate regions of low density which have not yet been modeled. The chosen orientation emphasizes the
planarity of the interface. The two-fold axis runs from the lefthand side in the front to the right hand side in the rear.
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The above figures are
reproduced from the cited reference
with permission from the Federation of European Biochemical Societies
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