Intrinsically Disordered Protein: Difference between revisions
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<StructureSection load='1jsu' size='450' side='right' scene='' caption=''> | |||
It has long been taught that proteins must be properly folded in order to perform their functions. This paradigm derives from work by | It has long been taught that proteins must be properly folded in order to perform their functions. This paradigm derives from work by | ||
Christian B. Anfinsen and coworkers. In the 1960's, they showed that RNAse, when denatured so that 99% of its enzymatic activity was lost, could regain enzymatic activity within seconds when the denaturing agent was removed under proper conditions<ref>For the sake of brevity, this description is oversimplified. RNAse needed to be reduced to break disulfide bonds, as well as using 8 M urea, for denaturation. Oxidation without the denaturant then left an inactive enzyme because the disulfide bonds formed randomly, precluding proper folding except very slowly (many hours). Only when protein disulfide isomerase was added did the re-folding occur at a physiological rate (about a minute). The fact that RNAse could thus be trapped in an inactive conformation under physiological conditions contributed to the insights developed by Anfinsen and his team. Proteins lacking disulfides renatured in seconds. For details, see [http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-lecture.html Anfinsen's Nobel Lecture.]</ref>. They concluded that the amino acid sequence is sufficient for a protein to fold into its functional, lowest energy conformation. This work won the [[Nobel_Prizes_for_3D_Molecular_Structure|1972 Nobel Prize]], and was subsequently confirmed and extended by many researchers. | Christian B. Anfinsen and coworkers. In the 1960's, they showed that RNAse, when denatured so that 99% of its enzymatic activity was lost, could regain enzymatic activity within seconds when the denaturing agent was removed under proper conditions<ref>For the sake of brevity, this description is oversimplified. RNAse needed to be reduced to break disulfide bonds, as well as using 8 M urea, for denaturation. Oxidation without the denaturant then left an inactive enzyme because the disulfide bonds formed randomly, precluding proper folding except very slowly (many hours). Only when protein disulfide isomerase was added did the re-folding occur at a physiological rate (about a minute). The fact that RNAse could thus be trapped in an inactive conformation under physiological conditions contributed to the insights developed by Anfinsen and his team. Proteins lacking disulfides renatured in seconds. For details, see [http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-lecture.html Anfinsen's Nobel Lecture.]</ref>. They concluded that the amino acid sequence is sufficient for a protein to fold into its functional, lowest energy conformation. This work won the [[Nobel_Prizes_for_3D_Molecular_Structure|1972 Nobel Prize]], and was subsequently confirmed and extended by many researchers. | ||
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=== The human p27<sup>Kip1</sup> kinase inhibitory domain <ref>PMID: 8684460</ref> === | === The human p27<sup>Kip1</sup> kinase inhibitory domain <ref>PMID: 8684460</ref> === | ||
The cyclin-dependent kinases (CDKs) have a central role in coordinating the eukaryotic cell division cycle. CDKs are controlled through several different processes involving the binding of activating cyclin subunits. Complexes of cyclins with CDKs play a central role in the control of the eukaryotic cell cycle. These complexes are inhibited by other proteins termed in general cyclin-CDK inhibitors (CKIs). One example of CKIs is p27<sup>Kip1</sup>. p27<sup>Kip1</sup> is an IUP and it binds to phosphorylated <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Complex/2'>cyclin/CDK complex</scene> in <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Extended/2'>an extended conformation</scene> interacting with both <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Cyca/2'>cyclin A</scene> and <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Cdk2/3'>CDK2</scene>. On cyclin A, it binds in a groove formed by conserved cyclin box residues. On CDK2, it binds and rearranges the amino-terminal lobe and also inserts into the catalytic cleft, mimicking ATP. [[http://www.proteopedia.org/wiki/index.php/1jsu]] | The cyclin-dependent kinases (CDKs) have a central role in coordinating the eukaryotic cell division cycle. CDKs are controlled through several different processes involving the binding of activating cyclin subunits. Complexes of cyclins with CDKs play a central role in the control of the eukaryotic cell cycle. These complexes are inhibited by other proteins termed in general cyclin-CDK inhibitors (CKIs). One example of CKIs is p27<sup>Kip1</sup>. p27<sup>Kip1</sup> is an IUP and it binds to phosphorylated <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Complex/2'>cyclin/CDK complex</scene> in <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Extended/2'>an extended conformation</scene> interacting with both <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Cyca/2'>cyclin A</scene> and <scene name='User:Tzviya_Zeev-Ben-Mordehai/Sandbox_1/Cdk2/3'>CDK2</scene>. On cyclin A, it binds in a groove formed by conserved cyclin box residues. On CDK2, it binds and rearranges the amino-terminal lobe and also inserts into the catalytic cleft, mimicking ATP. [[http://www.proteopedia.org/wiki/index.php/1jsu]] | ||
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=== The transcriptional activator GCN4 <ref>PMID: 8377181</ref>=== | === The transcriptional activator GCN4 <ref>PMID: 8377181</ref>=== | ||
The structure of GCN4 bound to a DNA fragment contains the perfectly symmetrical binding site ([[1dgc]]). A homodimer of parallel alpha-helices form an interhelix coiled-coil region via the leucine zipper, and the two N-terminal basic regions fit into the major groove of half sites on opposite sides of the DNA double helix. | |||
The yeast transcriptional activator GCN4 belongs to a large family of eukaryotic transcription factors including Fos, Jun and CREB. All family members have a [[DNA]] recognition motif consists of a coiled-coil dimerization element, the leucine-zipper, and an adjoining basic region, which mediates DNA binding. This basic region is largely unstructured in the absence of DNA, addition of DNA containing a GCN4 binding site induce the transition of this region from unstructured to α-helical. | The yeast transcriptional activator GCN4 belongs to a large family of eukaryotic transcription factors including Fos, Jun and CREB. All family members have a [[DNA]] recognition motif consists of a coiled-coil dimerization element, the leucine-zipper, and an adjoining basic region, which mediates DNA binding. This basic region is largely unstructured in the absence of DNA, addition of DNA containing a GCN4 binding site induce the transition of this region from unstructured to α-helical. | ||