Sandbox Reserved 197: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 17: | Line 17: | ||
The <scene name='Sandbox_Reserved_197/Cis-proline114/2'>Asn113-Pro114</scene> peptide bond also resides in a ''cis'' conformation in its folded structure, but exists in the ''trans'' conformation in its unfolded state; therefore, steric restraints imposed by the rest of the protein must be responsible for this ''cis'' conformation. Unlike P93A, the insertion of a <scene name='Sandbox_Reserved_197/P114g/2'>P114G</scene> point mutation causes the peptide bond to adopt a ''trans'' conformation and causes a 9.3 Å movement of the loop. The kinetic rate and overall native conformation are not significantly effected by this mutation; however, locally, a rearrangement of the hydrogen-bonding network occurs. Results of this mutation confirm that steric hinderance of the protein can lead to formation of the ''cis'' conformation by a proline and is further energetically stabilized by hydrogen bonding, Van der Waals, and electrostatic interactions within the protein. | The <scene name='Sandbox_Reserved_197/Cis-proline114/2'>Asn113-Pro114</scene> peptide bond also resides in a ''cis'' conformation in its folded structure, but exists in the ''trans'' conformation in its unfolded state; therefore, steric restraints imposed by the rest of the protein must be responsible for this ''cis'' conformation. Unlike P93A, the insertion of a <scene name='Sandbox_Reserved_197/P114g/2'>P114G</scene> point mutation causes the peptide bond to adopt a ''trans'' conformation and causes a 9.3 Å movement of the loop. The kinetic rate and overall native conformation are not significantly effected by this mutation; however, locally, a rearrangement of the hydrogen-bonding network occurs. Results of this mutation confirm that steric hinderance of the protein can lead to formation of the ''cis'' conformation by a proline and is further energetically stabilized by hydrogen bonding, Van der Waals, and electrostatic interactions within the protein. | ||
Another important role of proline residues is their involvement in β turns. β turns are 180° turns commonly found in globular proteins to allow for a compact structure by connecting the ends of adjacent antiparallel β sheets [http://en.wikipedia.org/wiki/Beta_sheet]. The turn consists of a sequence of four amino acid residues. The carbonyl of the first amino acid hydrogen bonds with the amino group of the fourth amino acid. Proline is involved in β turns because it is small and flexible and assumes a ''cis'' conformation. In RNase A both Pro93 and Pro114 are involved in β turns. | |||
<Structure load='7RSA' size='500' frame='true' align='left' caption='Insert caption here' scene='Sandbox_Reserved_197/Rnase_a_wild_type/4' /> | <Structure load='7RSA' size='500' frame='true' align='left' caption='Insert caption here' scene='Sandbox_Reserved_197/Rnase_a_wild_type/4' /> | ||
