Turns in Proteins
From Proteopedia
| Line 1: | Line 1: | ||
| - | <Structure load='1abb' size='500' frame='true' align='right' caption='' scene='Turns_in_Proteins/Hemery/ | + | <Structure load='1abb' size='500' frame='true' align='right' caption='' scene='Turns_in_Proteins/Hemery/4' /> |
Since turns are classified as a type of secondary structure, they have an ordered, repetitive structure. There are about six different classes of β-turns with all of them containing four residues, but each class has a different range of psi and phi values for the second and third residues. Pro and Gly are commonly found in positions two and three, respectively, because their unique side chains permit a sharp bend in the peptide chain. A hydrogen bond formed between the backbond atoms of residues one and four is the major force maintaining the conformation of the bend in the chain, and in one class a Pro in the third position has the cis configuration which maintains the sharp bend without the aid of a hydrogen bond. | Since turns are classified as a type of secondary structure, they have an ordered, repetitive structure. There are about six different classes of β-turns with all of them containing four residues, but each class has a different range of psi and phi values for the second and third residues. Pro and Gly are commonly found in positions two and three, respectively, because their unique side chains permit a sharp bend in the peptide chain. A hydrogen bond formed between the backbond atoms of residues one and four is the major force maintaining the conformation of the bend in the chain, and in one class a Pro in the third position has the cis configuration which maintains the sharp bend without the aid of a hydrogen bond. | ||
| - | Seven β-turns are shown as blue traces in myohemerytherin in the scene to the right. In two cases one β-turn follows another one so the blue traces are longer, and five of the turns contain hydrogen bonds shown in magenta. | + | Seven β-turns are shown as blue traces in myohemerytherin in the scene to the right. In two cases one β-turn follows another one so the blue traces are longer, and five of the turns contain hydrogen bonds shown in magenta. Turns shown in <scene name='Turns_in_Proteins/Hemery_wf/2'>wireframe</scene> without the side chains so that the backbone atoms can be seen. One can now clearly see that the hydrogen bonds are positioned between the first and the fourth residues of the turn. |
<scene name='Turns_in_Proteins/Gly_phosyl/3'>Domain 2</scene> chain a glycogen phosphorylase. | <scene name='Turns_in_Proteins/Gly_phosyl/3'>Domain 2</scene> chain a glycogen phosphorylase. | ||
| Line 10: | Line 10: | ||
<scene name='Turns_in_Proteins/Gly_phosyl_turn1/2'>One turn</scene>. <scene name='Turns_in_Proteins/Gly_phosyl_turn2/1'>Psi and phi</scene> of first turn. | <scene name='Turns_in_Proteins/Gly_phosyl_turn1/2'>One turn</scene>. <scene name='Turns_in_Proteins/Gly_phosyl_turn2/1'>Psi and phi</scene> of first turn. | ||
<scene name='Turns_in_Proteins/Gly_phosyl_turn_b/1'>Double turn</scene> | <scene name='Turns_in_Proteins/Gly_phosyl_turn_b/1'>Double turn</scene> | ||
| - | <scene name='Turns_in_Proteins/Hemery/ | + | <scene name='Turns_in_Proteins/Hemery/4'>hemerytherin</scene> |
Revision as of 17:28, 3 March 2011
|
Since turns are classified as a type of secondary structure, they have an ordered, repetitive structure. There are about six different classes of β-turns with all of them containing four residues, but each class has a different range of psi and phi values for the second and third residues. Pro and Gly are commonly found in positions two and three, respectively, because their unique side chains permit a sharp bend in the peptide chain. A hydrogen bond formed between the backbond atoms of residues one and four is the major force maintaining the conformation of the bend in the chain, and in one class a Pro in the third position has the cis configuration which maintains the sharp bend without the aid of a hydrogen bond.
Seven β-turns are shown as blue traces in myohemerytherin in the scene to the right. In two cases one β-turn follows another one so the blue traces are longer, and five of the turns contain hydrogen bonds shown in magenta. Turns shown in without the side chains so that the backbone atoms can be seen. One can now clearly see that the hydrogen bonds are positioned between the first and the fourth residues of the turn.
chain a glycogen phosphorylase.
. of first turn.
