Sandbox Reserved 1846: Difference between revisions

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=== F243 ===
=== F243 ===
<scene name='10/1075247/F243/3'>F243</scene>
<scene name='10/1075247/Better_f234/3'>F243</scene>


<scene name='10/1075247/I243/3'>F243I</scene>
<scene name='10/1075247/Better_f243i/2'>F243I</scene>


F243W
F243W


The original side chain at position 243 is phenylalanine, which is located 3.6 Å from the ligand. Two mutations at this position—F243I (isoleucine) and F243W (tryptophan)—increase the catalytic activity of the enzyme. The F243I mutation replaces phenylalanine with isoleucine, a smaller side chain that allows the ligand to sit closer. This reduces the ligand distance to 3.0 Å. This tighter interaction likely improves substrate binding. The F243W mutation introduces tryptophan, which has a bulkier, nitrogen-containing aromatic side chain. Tryptophan brings the ligand slightly closer at 3.2 Å and introduces potential for new interactions, such as hydrogen bonding or π-stacking. Both mutations result in improved catalytic performance. The F243I mutation leads to a 27.5% increase in activity, while the F243W mutation results in a 17.5% increase, compared to the wild-type enzyme.
The original side chain at position 243 is phenylalanine, which is located 3.6 Å from the ligand. Two mutations at this position—F243I (isoleucine) and F243W (tryptophan)—increase the catalytic activity of the enzyme. The F243I mutation replaces phenylalanine with isoleucine, a smaller side chain that allows the ligand to sit closer. This reduces the ligand distance to 3.0 Å. This tighter interaction likely improves substrate binding. The F243W mutation introduces tryptophan, which has a bulkier, nitrogen-containing aromatic side chain. Tryptophan brings the ligand slightly closer at 3.2 Å and introduces potential for new interactions, such as hydrogen bonding or π-stacking. Both mutations result in improved catalytic performance. The F243I mutation leads to a 27.5% increase in activity, while the F243W mutation results in a 17.5% increase, compared to the wild-type enzyme.
=== T96 ===
<scene name='10/1075247/T96/3'>T96</scene>


T96M
The mutation of threonine to methionine at position 96 (M96) increases the protein's thermostability. Threonine has a small, polar side chain, which makes it hydrophilic and less stable at higher temperatures. Methionine, however, has a larger, nonpolar, and hydrophobic side chain, which strengthens hydrophobic interactions in the protein’s core. These stronger internal interactions help stabilize the protein and help it to maintain its folded structure at higher temperatures. As a result, the melting point increases from 84.7°C for the wild-type protein to 87.4°C for the M96 mutant.


=== Y127 ===
=== Y127 ===
<scene name='10/1075247/Y127/1'>Y127</scene>
<scene name='10/1075247/Y127/4'>Y127</scene>


<scene name='10/1075247/G127/1'>Y127G</scene>
<scene name='10/1075247/Y127g/2'>Y127G</scene>


The mutation of tyrosine to glycine at position 127 (Y127G) also increases the protein's thermostability. The mutant melting point is increased to 87.0°C. Tyrosine has a bulky, rigid aromatic side chain that can cause structural strain. Glycine is the smallest amino acid and lacks a side chain, so it provides greater flexibility to the protein. This mutation reduces steric hindrance and relieves strain in the protein structure, therefore allowing it to be more adaptable and stable at higher temperatures. By increasing flexibility, the Y127G mutation helps the protein maintain its folded structure under heat stress.
The mutation of tyrosine to glycine at position 127 (Y127G) also increases the protein's thermostability. The mutant melting point is increased to 87.0°C. Tyrosine has a bulky, rigid aromatic side chain that can cause structural strain. Glycine is the smallest amino acid and lacks a side chain, so it provides greater flexibility to the protein. This mutation reduces steric hindrance and relieves strain in the protein structure, therefore allowing it to be more adaptable and stable at higher temperatures. By increasing flexibility, the Y127G mutation helps the protein maintain its folded structure under heat stress.
=== N246 ===
<scene name='10/1075247/N246/1'>N246</scene>
N246D
N246M
The asparagine side chain is mutated to aspartic acid and methionine to increase thermostability. The wild-type protein has a melting point of 84.7°C. The N246D mutation (asparagine to aspartic acid) replaces a polar neutral side chain with a negatively charged one, which potentially increases electrostatic interactions or salt bridges that stabilize the protein. This results in a melting point of 87.9°C. The N246M mutation (asparagine to methionine) introduces a bulkier, hydrophobic side chain. This increases the internal packing of the protein core. This mutant has a melting point of 88.0°C.


=== S283 & D238 ===
=== S283 & D238 ===
<scene name='10/1075248/S283-d238/1'>S283 and D238</scene>
<scene name='10/1075247/S283-d238/5'>S283 and D238</scene>


<scene name='10/1075248/C283-c238/1'>S283C and D238C</scene>
<scene name='10/1075248/C283-c238/1'>S283C and D238C</scene>
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