Telomerase Reverse Transcriptase: Difference between revisions
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Telomerase is a ribonucleoprotein enzyme. It adds specific telomeric DNA repeats to the 3'ends of linear chromosomes. | Telomerase is a ribonucleoprotein enzyme. It adds specific telomeric DNA repeats to the 3'ends of linear chromosomes. | ||
It was discovered in 1985 by Freider and Blackburn in ''Tetrahymena''. Basically the Telomerase includes an '''RNA (TR) subunit''' and a subunit called '''Telomerase Reverse Transcriptase (TERT)'''. The function of the '''TR''' subunit is to provide the template for telomeric DNA synthesis, which is done by the TERT. | It was discovered in 1985 by Freider and Blackburn in ''Tetrahymena''. Basically the Telomerase includes an '''RNA (TR) subunit''' and a subunit called '''Telomerase Reverse Transcriptase (TERT)'''. The function of the '''TR''' subunit is to provide the template for telomeric DNA synthesis, which is done by the TERT. | ||
The structure of TERT is similar to other reverse transcriptases in their catalytic domain. In contrast to other reverse transcriptases the TERTs have a large N-terminal extension which is called '''TERT essential N-terminal (TEN) domain'''. <PMID: 16462747> | The structure of TERT is similar to other reverse transcriptases in their catalytic domain. In contrast to other reverse transcriptases the TERTs have a large N-terminal extension which is called '''TERT essential N-terminal (TEN) domain'''. <ref>PMID: 16462747</ref> | ||
TEN form stable interactions with the telomerase RNA (TR) subunit. | TEN form stable interactions with the telomerase RNA (TR) subunit. | ||
Binding of the RNA subunit is possible, because of the presence of TEN in TERTs. | Binding of the RNA subunit is possible, because of the presence of TEN in TERTs. | ||
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== '''Experimental fragment with TEN''' == | == '''Experimental fragment with TEN''' == | ||
<applet load='2b2a' size='400' frame='true' align='right' caption=' | <applet load='2b2a' size='400' frame='true' align='right' caption='Tetrahymena thermophila telomerase reverse transcriptase TEN domain [[2b2a]]' scene='Sandbox/Presentation/3' /> | ||
A Tetrahymena Thermophila TERT fragment consisting of residues 2-191 with an N-terminal His6 tag was cristallized in space group P3 with <scene name='Sandbox/Three/1'>three</scene> TERT molecules present in the crystallographic asymmetric unit. | A Tetrahymena Thermophila TERT fragment consisting of residues 2-191 with an N-terminal His6 tag was cristallized in space group P3 with <scene name='Sandbox/Three/1'>three</scene> TERT molecules present in the crystallographic asymmetric unit. | ||
This 23.5-kDa fragment contains only one methionine residue, making phasing by substitution with selenomethionine (SeMet) difficult. | This 23.5-kDa fragment contains only one methionine residue, making phasing by substitution with selenomethionine (SeMet) difficult. | ||
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Development of cancer chemotherapeutics directed against the reverse-transcriptase domain of telomerase has been challenging, perhaps because the enzyme needs only low activity to maintain telomeres. | Development of cancer chemotherapeutics directed against the reverse-transcriptase domain of telomerase has been challenging, perhaps because the enzyme needs only low activity to maintain telomeres. | ||
Because the TEN domain is essential for telomerase activity and its structure seems to be conserved trough evolution, this portion of TERT is a potential new target for antitelomerase compounds. | Because the TEN domain is essential for telomerase activity and its structure seems to be conserved trough evolution, this portion of TERT is a potential new target for antitelomerase compounds. | ||
==3D structures of telomerase reverse transcriptase== | |||
See [[Telomerase]] | |||
=='''Additional Resources'''== | |||
For additional information, See: [[Cancer]] | |||
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== '''References''' == | == '''References''' == | ||
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==User contributions== | ==User contributions== | ||
This page was created with content | This page was created with content from a page authored by [[User:Tanja Emmerich]] and [[User:Vinzenz Alejandro Bayro Kaiser]]. | ||
[[Category:Topic Page]] | |||