Sandbox Reserved 1260
From Proteopedia
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==Topoisomerase I== | ==Topoisomerase I== | ||
<StructureSection load='1A36' size='340' side='right' caption='Topoisomerase I' scene=''> | <StructureSection load='1A36' size='340' side='right' caption='Topoisomerase I' scene=''> | ||
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+ | Topoisomerase I is an enzyme that winds and unwinds the DNA double helix in order to increase or decrease supercoiling. By controlling supercoiling, topoisomerase indirectly controls DNA transcription, as a highly supercoiled molecule is difficult to transcribe while a relaxed helix is easier to access. This enzyme exists in both prokaryotes and eukaryotes. | ||
== Function == | == Function == | ||
The <scene name='75/751153/Acidic_and_basic_residues/1'>amino acid residues</scene> on the topoisomerase are responsible for catalyzing the phosphodiester cleavage reactions. | The <scene name='75/751153/Acidic_and_basic_residues/1'>amino acid residues</scene> on the topoisomerase are responsible for catalyzing the phosphodiester cleavage reactions. | ||
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+ | 1. Topoisomerase binds to DNA and cuts one strand while simultaneously forming a covalent phosphoester bond b/w the 5’ end of the cut DNA strand one of topoisomerase’s tyrosine residues. | ||
+ | 2. Topoisomerase holds the free 3’ end of cut DNA noncovalently. | ||
+ | 3. The non-cleaved DNA strand is passed through the cleaved ends. | ||
+ | 4. The cleaved strand is reattached, unwinding the helix. | ||
== Structural highlights == | == Structural highlights == |
Revision as of 21:16, 7 February 2017
==genetics is ok==
Contents |
'Molecules it Interacts With and where '
The protein binds to GDP as well as the following ligands in order to promote the attachment of the protein complex to the ribosome A site.
PHOSHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
PHENYLALANINE
MAGNESIUM ION
'Origin'
It has domains that are created in yeast (phenyl-transfer RNA) , in the heat resistant Thermus aquaticus (EF-Tu elongation factor, and can be synthetically manufactured.
'Structure'
It has 3 domains. G proteins, Elongation Factors, and the EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain. It is composed of 6 chains, which combine in alignment.
Specific are highlighted here. The ligands listed above, GDP, Phe, and Mg+2 ion each attach at these locations which are still being explored.
which play a crucial role in binding to the ribosome during translation. They form positive pockets with which negative amino acids can bind to.
'Molecules it Interacts With and where '
The protein binds to GDP as well as the following ligands in order to promote the attachment of the protein complex to the ribosome A site.
PHOSHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
PHENYLALANINE
MAGNESIUM ION
'Origin'
It has domains that are created in yeast (phenyl-transfer RNA) , in the heat resistant Thermus aquaticus (EF-Tu elongation factor, and can be synthetically manufactured.
'Structure'
It has 3 domains. G proteins, Elongation Factors, and the EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain. It is composed of 6 chains, which combine in alignment.
Specific are highlighted here.
which play a crucial role in binding to the ribosome during translation.
'Function"
The protein complex participates in placing the amino acids in their correct order when messenger RNA is translated into a protein sequence on the ribosome by promoting GTP-dependent binding of tRNA to the A site of the ribosome. In other words, it is involved with elongation during polypeptide synthesis.
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Topoisomerase I
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