Sheets in Proteins
From Proteopedia
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<Structure load='Silk 64.mol' size='500' frame='true' align='right' caption='' scene='Sheets_in_Proteins/Syn_sheet1/2' /> | <Structure load='Silk 64.mol' size='500' frame='true' align='right' caption='' scene='Sheets_in_Proteins/Syn_sheet1/2' /> | ||
| - | A β-pleated sheet contains multiple peptide strands that are positioned adjacent to one another as the one shown on the right<ref>This model was hand constructed using HyperChem</ref>. The planes of the <scene name='Sheets_in_Proteins/Syn_sheet2/2'>pleats</scene> are formed by the planes of the peptide bond. The alpha carbons of the peptide chain are at the valleys and peaks of the pleats. The peptides are <scene name='Sheets_in_Proteins/Syn_sheet3/3'>rainbow colored</scene> (blue amino end changing to red carboxy end) to show that the adjacent peptides are running in opposite directions making the sheet antiparallel. Another way of detecting the <scene name='Sheets_in_Proteins/Syn_sheet7/1'>antiparallel sheet</scene> is by displaying as cartoon. The adjacent chains align so that <scene name='Sheets_in_Proteins/Syn_sheet4/1'>hydrogne bonds</scene> are formed between the imino hydrogens of one chain and the carbonyl oxygens of an adjacent chain. These hydrogen bonds provide the major attractive force which maintains the sheet structure. Psi and phi values that permit this alignment in antiparallel sheets have <scene name='Sheets_in_Proteins/Syn_sheet5/1'>mean values</scene> of 135<sup>0</sup> and -139<sup>0</sup>, respectively. The mean values for a parallel sheet are . | + | A β-pleated sheet contains multiple peptide strands that are positioned adjacent to one another as the one shown on the right<ref>This model was hand constructed using HyperChem and setting all psi and phi values to 135<sup>0</sup> and -139<sup>0</sup>, respectively.</ref>. The planes of the <scene name='Sheets_in_Proteins/Syn_sheet2/2'>pleats</scene> are formed by the planes of the peptide bond. The alpha carbons of the peptide chain are at the valleys and peaks of the pleats. The peptides are <scene name='Sheets_in_Proteins/Syn_sheet3/3'>rainbow colored</scene> (blue amino end changing to red carboxy end) to show that the adjacent peptides are running in opposite directions making the sheet antiparallel. Another way of detecting the <scene name='Sheets_in_Proteins/Syn_sheet7/1'>antiparallel sheet</scene> is by displaying as cartoon. The adjacent chains align so that <scene name='Sheets_in_Proteins/Syn_sheet4/1'>hydrogne bonds</scene> are formed between the imino hydrogens of one chain and the carbonyl oxygens of an adjacent chain. These hydrogen bonds provide the major attractive force which maintains the sheet structure. Psi and phi values that permit this alignment in antiparallel sheets have <scene name='Sheets_in_Proteins/Syn_sheet5/1'>mean values</scene> of 135<sup>0</sup> and -139<sup>0</sup>, respectively. The mean values for a parallel sheet are . |
| - | Twisted sheets are found in globular proteins. Unlike the <scene name='Sheets_in_Proteins/Syn_sheet6/ | + | Twisted sheets are found in globular proteins. Unlike the <scene name='Sheets_in_Proteins/Syn_sheet6/2'>above two types</scene> of sheets the valleys and the peaks of a <scene name='Sheets_in_Proteins/Gly_phosyl2/2'>twisted sheet</scene><ref>Sheet present in domain 2 of glycogen phosphorylase (PDB code [[1abb]]).</ref> do not fall on parallel lines. Observe that the sheet is <scene name='Sheets_in_Proteins/Gly_phosyl/4'>parallel</scene>, and showing <scene name='Sheets_in_Proteins/Gly_phosyl3/1'>hydrogen bonds</scene>. Notice that in contrast to the hydrogen bonds of the antiparallel sheet shown above where the bonds were parallel here the bonds are diagonal to each other. Show <scene name='Sheets_in_Proteins/Gly_phosyl5/2'>psi and phi values</scene> for randomly chosen residues. There are a wide range of values for both psi and phi, 96 to 148 and -108 to -142. Sheet shown in the context of <scene name='Sheets_in_Proteins/Gly_phosyl4/1'>domain 2</scene> of glycogen phosphorylase. Examples of <scene name='Sheets_in_Proteins/1dtg1/1'>antiparallel sheets</scene> are in human transferrin n-lobe mutant (PDB code [[1dtg]]). Showing only the <scene name='Sheets_in_Proteins/1dtg2/2'>sheets</scene>, and with <scene name='Sheets_in_Proteins/1dtg3/1'>hydrogen bonds</scene>. |
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Revision as of 14:57, 17 February 2011
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A β-pleated sheet contains multiple peptide strands that are positioned adjacent to one another as the one shown on the right[1]. The planes of the are formed by the planes of the peptide bond. The alpha carbons of the peptide chain are at the valleys and peaks of the pleats. The peptides are (blue amino end changing to red carboxy end) to show that the adjacent peptides are running in opposite directions making the sheet antiparallel. Another way of detecting the is by displaying as cartoon. The adjacent chains align so that are formed between the imino hydrogens of one chain and the carbonyl oxygens of an adjacent chain. These hydrogen bonds provide the major attractive force which maintains the sheet structure. Psi and phi values that permit this alignment in antiparallel sheets have of 1350 and -1390, respectively. The mean values for a parallel sheet are .
Twisted sheets are found in globular proteins. Unlike the of sheets the valleys and the peaks of a [2] do not fall on parallel lines. Observe that the sheet is , and showing . Notice that in contrast to the hydrogen bonds of the antiparallel sheet shown above where the bonds were parallel here the bonds are diagonal to each other. Show for randomly chosen residues. There are a wide range of values for both psi and phi, 96 to 148 and -108 to -142. Sheet shown in the context of of glycogen phosphorylase. Examples of are in human transferrin n-lobe mutant (PDB code 1dtg). Showing only the , and with .
Notes and References
- ↑ This model was hand constructed using HyperChem and setting all psi and phi values to 1350 and -1390, respectively.
- ↑ Sheet present in domain 2 of glycogen phosphorylase (PDB code 1abb).
Proteopedia Page Contributors and Editors (what is this?)
Karl Oberholser, Karsten Theis, Jaime Prilusky, Eric Martz, Angel Herraez
