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Structures of native human thymidine phosphorylase and in complex with 5-iodouracil.

Mitsiki E, Papageorgiou AC, Iyer S, Thiyagarajan N, Prior SH, Sleep D, Finnis C, Acharya KR - Biochem. Biophys. Res. Commun. (2009)

Bottom Line: Thymidine phosphorylase (TP) first identified as platelet derived endothelial cell growth factor (PD-ECGF) plays a key role in nucleoside metabolism.Human TP (hTP) is implicated in angiogenesis and is overexpressed in several solid tumors.In addition, we provide information on the role of specific residues in the enzymatic activity of hTP through mutagenesis and kinetic studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.

ABSTRACT
Thymidine phosphorylase (TP) first identified as platelet derived endothelial cell growth factor (PD-ECGF) plays a key role in nucleoside metabolism. Human TP (hTP) is implicated in angiogenesis and is overexpressed in several solid tumors. Here, we report the crystal structures of recombinant hTP and its complex with a substrate 5-iodouracil (5IUR) at 3.0 and 2.5A, respectively. In addition, we provide information on the role of specific residues in the enzymatic activity of hTP through mutagenesis and kinetic studies.

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(A) Superposition of hTP molecule in the native (gray) and in complex with 5IUR (light orange). Highlighted in green are the three loops (L1–L3) and in magenta is the hinge region. (B) Crystal packing of hTP–5IUR complex. The figures were created using Pymol (www.pymol.org). (C) Stereo view of the active site with bound 5IUR in the hTP–5IUR complex. Potential hydrogen bonds are illustrated with dotted lines. The electron density map (2Fo − Fc) around 5IUR is contoured at 1.0σ level. The figure was created using Molscript [24].
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fig1: (A) Superposition of hTP molecule in the native (gray) and in complex with 5IUR (light orange). Highlighted in green are the three loops (L1–L3) and in magenta is the hinge region. (B) Crystal packing of hTP–5IUR complex. The figures were created using Pymol (www.pymol.org). (C) Stereo view of the active site with bound 5IUR in the hTP–5IUR complex. Potential hydrogen bonds are illustrated with dotted lines. The electron density map (2Fo − Fc) around 5IUR is contoured at 1.0σ level. The figure was created using Molscript [24].

Mentions: The crystal structure of native hTP (at 3.0 Å) (Fig. 1A) consists of two non-crystallographic dimers in the asymmetric unit. All four copies of hTP contain residues 34–479, residues 32 and 33 can be observed for chains A and B while only residue 33 can be observed for molecule C. At the C-terminal end, residue 480 was observed only in chain B. The crystal structure of hTP–5IUR complex (at 2.5 Å) consists of a dimer per asymmetric unit (Fig. 1B). Both chains comprise of residues 35–480 with one molecule of 5IUR bound in the active site of each hTP molecule.


Structures of native human thymidine phosphorylase and in complex with 5-iodouracil.

Mitsiki E, Papageorgiou AC, Iyer S, Thiyagarajan N, Prior SH, Sleep D, Finnis C, Acharya KR - Biochem. Biophys. Res. Commun. (2009)

(A) Superposition of hTP molecule in the native (gray) and in complex with 5IUR (light orange). Highlighted in green are the three loops (L1–L3) and in magenta is the hinge region. (B) Crystal packing of hTP–5IUR complex. The figures were created using Pymol (www.pymol.org). (C) Stereo view of the active site with bound 5IUR in the hTP–5IUR complex. Potential hydrogen bonds are illustrated with dotted lines. The electron density map (2Fo − Fc) around 5IUR is contoured at 1.0σ level. The figure was created using Molscript [24].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2719695&req=5

fig1: (A) Superposition of hTP molecule in the native (gray) and in complex with 5IUR (light orange). Highlighted in green are the three loops (L1–L3) and in magenta is the hinge region. (B) Crystal packing of hTP–5IUR complex. The figures were created using Pymol (www.pymol.org). (C) Stereo view of the active site with bound 5IUR in the hTP–5IUR complex. Potential hydrogen bonds are illustrated with dotted lines. The electron density map (2Fo − Fc) around 5IUR is contoured at 1.0σ level. The figure was created using Molscript [24].
Mentions: The crystal structure of native hTP (at 3.0 Å) (Fig. 1A) consists of two non-crystallographic dimers in the asymmetric unit. All four copies of hTP contain residues 34–479, residues 32 and 33 can be observed for chains A and B while only residue 33 can be observed for molecule C. At the C-terminal end, residue 480 was observed only in chain B. The crystal structure of hTP–5IUR complex (at 2.5 Å) consists of a dimer per asymmetric unit (Fig. 1B). Both chains comprise of residues 35–480 with one molecule of 5IUR bound in the active site of each hTP molecule.

Bottom Line: Thymidine phosphorylase (TP) first identified as platelet derived endothelial cell growth factor (PD-ECGF) plays a key role in nucleoside metabolism.Human TP (hTP) is implicated in angiogenesis and is overexpressed in several solid tumors.In addition, we provide information on the role of specific residues in the enzymatic activity of hTP through mutagenesis and kinetic studies.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.

ABSTRACT
Thymidine phosphorylase (TP) first identified as platelet derived endothelial cell growth factor (PD-ECGF) plays a key role in nucleoside metabolism. Human TP (hTP) is implicated in angiogenesis and is overexpressed in several solid tumors. Here, we report the crystal structures of recombinant hTP and its complex with a substrate 5-iodouracil (5IUR) at 3.0 and 2.5A, respectively. In addition, we provide information on the role of specific residues in the enzymatic activity of hTP through mutagenesis and kinetic studies.

Show MeSH
Related in: MedlinePlus