Globular Proteins: Difference between revisions
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== Other Characteristics == | == Other Characteristics == | ||
Disulfide bonds and metal ion chelates can stabilize the tertiary structure in the absence of well organized layers which generate hydrophobic attractions. Some proteins are small in size and therefore do not have large amounts of backbone that can be organized into layers. Others have significant backbone, but the layers are not well organized and therefore are non-stabilizing. The attractions formed by metal ions chelates or disulfide bonds in these proteins are as important or more so than the hydrophobic interactions of the organized layers. Examples of both types will be given. | Disulfide bonds and metal ion chelates can stabilize the tertiary structure in the absence of well organized layers which generate hydrophobic attractions. Some proteins are small in size and therefore do not have large amounts of backbone that can be organized into layers. Others have significant backbone, but the layers are not well organized and therefore are non-stabilizing. The attractions formed by metal ions chelates or disulfide bonds in these proteins are as important or more so than the hydrophobic interactions of the organized layers. Examples of both types of bonds will be given. | ||
Some proteins are intrinsically unstructured. They do have secondary structure, but these structural components are not extensively folded back on themselves resulting in a more extended conformation. With this extended conformation these proteins do not have binding pockets normally found in globular proteins so as a consequence binding to these proteins occurs over a relatively large surface area. Examples will illustrate the extended conformation as well as the large binding surface. | Some proteins are intrinsically unstructured. They do have secondary structure, but these structural components are not extensively folded back on themselves resulting in a more extended conformation. As is the case with most classifications of nature the distinction between folded globular proteins and intrinsically unstructured proteins is not sharp. With this extended conformation these proteins do not have binding pockets normally found in globular proteins so as a consequence binding to these proteins occurs over a relatively large surface area. Examples will illustrate the extended conformation as well as the large binding surface. | ||
<StructureSection load='2ben' size='500' side='right' caption='' scene='Globular_Proteins/Insulin1/1'>__NOTOC__ | <StructureSection load='2ben' size='500' side='right' caption='' scene='Globular_Proteins/Insulin1/1'>__NOTOC__ | ||
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=== Intrinsically Unstructured Proteins === | === Intrinsically Unstructured Proteins === | ||
<scene name='Globular_Proteins/Catenin/2'>β-catenin</scene> - one of several catenin. You may notice that residues 550-561 are missing most likely because they form an unordered segment. Show | <scene name='Globular_Proteins/Catenin/2'>β-catenin</scene> - one of several catenin. You may notice that residues 550-561 are missing, and these residues are most likely missing because they form an unordered segment. Show <scene name='Globular_Proteins/Catenin3/1'>lymphoid enhancer-binding factor 1</scene> (LEF-1) bound to β-catenin. LEF-1 is missing residues 26-47, again an unordered segment. Fill in this gap in your mind's eye, and you will see the large area over which the LEF-1 is binding. | ||