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1lpq
From Proteopedia
(New page: 200px<br /> <applet load="1lpq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lpq, resolution 3.14Å" /> '''Human DNA Topoisome...) |
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| - | [[Image:1lpq.gif|left|200px]]<br /> | + | [[Image:1lpq.gif|left|200px]]<br /><applet load="1lpq" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1lpq" size=" | + | |
caption="1lpq, resolution 3.14Å" /> | caption="1lpq, resolution 3.14Å" /> | ||
'''Human DNA Topoisomerase I (70 Kda) In Non-Covalent Complex With A 22 Base Pair DNA Duplex Containing an 8-oxoG Lesion'''<br /> | '''Human DNA Topoisomerase I (70 Kda) In Non-Covalent Complex With A 22 Base Pair DNA Duplex Containing an 8-oxoG Lesion'''<br /> | ||
==Overview== | ==Overview== | ||
| - | 7,8-Dihydro-8-oxoguanine (8-oxoG) is the most common form of oxidative DNA | + | 7,8-Dihydro-8-oxoguanine (8-oxoG) is the most common form of oxidative DNA damage in human cells. Biochemical studies have shown that 8-oxoG decreases the DNA cleavage activity of human topoisomerase I, an enzyme vital to DNA metabolism and stability. We present the 3.1-A crystal structure of human topoisomerase I in noncovalent complex with a DNA oligonucleotide containing 8-oxoG at the +1 position in the scissile strand. We find that 8-oxoG reorganizes the active site of human topoisomerase I into an inactive conformation relative to the structures of topoisomerase I-DNA complexes elucidated previously. The catalytic Tyr-723-Phe rotates away from the DNA cleavage site and packs into the body of the molecule. A second active-site residue, Arg-590, becomes disordered and is not observed in the structure. The docked, inactive conformation of Tyr-723-Phe is reminiscent of the related tyrosine recombinase family of integrases and recombinases, suggesting a common regulatory mechanism. We propose that human topoisomerase I binds to DNA first in an inactive conformation and then rearranges its active site for catalysis. 8-OxoG appears to impact topoisomerase I by stabilizing the inactive, DNA-bound state. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1LPQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/DNA_topoisomerase DNA topoisomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.2 5.99.1.2] Full crystallographic information is available from [http:// | + | 1LPQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/DNA_topoisomerase DNA topoisomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.2 5.99.1.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LPQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Lesher, D | + | [[Category: Lesher, D T.]] |
[[Category: Pommier, Y.]] | [[Category: Pommier, Y.]] | ||
| - | [[Category: Redinbo, M | + | [[Category: Redinbo, M R.]] |
[[Category: Stewart, L.]] | [[Category: Stewart, L.]] | ||
[[Category: dna damage]] | [[Category: dna damage]] | ||
| Line 26: | Line 25: | ||
[[Category: protein-dna complex]] | [[Category: protein-dna complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:47:14 2008'' |
Revision as of 11:47, 21 February 2008
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Human DNA Topoisomerase I (70 Kda) In Non-Covalent Complex With A 22 Base Pair DNA Duplex Containing an 8-oxoG Lesion
Contents |
Overview
7,8-Dihydro-8-oxoguanine (8-oxoG) is the most common form of oxidative DNA damage in human cells. Biochemical studies have shown that 8-oxoG decreases the DNA cleavage activity of human topoisomerase I, an enzyme vital to DNA metabolism and stability. We present the 3.1-A crystal structure of human topoisomerase I in noncovalent complex with a DNA oligonucleotide containing 8-oxoG at the +1 position in the scissile strand. We find that 8-oxoG reorganizes the active site of human topoisomerase I into an inactive conformation relative to the structures of topoisomerase I-DNA complexes elucidated previously. The catalytic Tyr-723-Phe rotates away from the DNA cleavage site and packs into the body of the molecule. A second active-site residue, Arg-590, becomes disordered and is not observed in the structure. The docked, inactive conformation of Tyr-723-Phe is reminiscent of the related tyrosine recombinase family of integrases and recombinases, suggesting a common regulatory mechanism. We propose that human topoisomerase I binds to DNA first in an inactive conformation and then rearranges its active site for catalysis. 8-OxoG appears to impact topoisomerase I by stabilizing the inactive, DNA-bound state.
Disease
Known disease associated with this structure: DNA topoisomerase I, camptothecin-resistant OMIM:[126420]
About this Structure
1LPQ is a Single protein structure of sequence from Homo sapiens. Active as DNA topoisomerase, with EC number 5.99.1.2 Full crystallographic information is available from OCA.
Reference
8-Oxoguanine rearranges the active site of human topoisomerase I., Lesher DT, Pommier Y, Stewart L, Redinbo MR, Proc Natl Acad Sci U S A. 2002 Sep 17;99(19):12102-7. Epub 2002 Sep 3. PMID:12209008
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