Extremophile: Difference between revisions

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Calculate along the chain, in the N to C-terminal direction how just several amino acid switches bring the positive net charge of whale myoglobin up to ''+4'' and elephants to ''+2'': (summing up the total charge of the protein) <scene name='52/523344/Elephantwhale/19'>residue position 8</scene> (<span style="color:red">'''glu'''</span> in elephents versus gln in whales), <scene name='52/523344/Elephantwhale/21'>12</scene> (<span style="color:blue">'''lys'''</span>  vs. <span style="color:lightblue">'''his'''</span>), <scene name='52/523344/Elephantwhale/22'>27</scene> (thr vs. <span style="color:red">'''asp'''</span>), <scene name='52/523344/Elephantwhale/23'>34</scene> (thr vs. <span style="color:blue">'''lys'''</span> ), <scene name='52/523344/Elephantwhale/24'>87</scene> (gln vs. <span style="color:blue">'''lys'''</span> ), <scene name='52/523344/Elephantwhale/26'>116</scene> (gln vs. <span style="color:lightblue">'''his'''</span>), <scene name='52/523344/Elephantwhale/27'>132</scene> (<span style="color:blue">'''lys'''</span>  vs. asn), <scene name='52/523344/Elephantwhale/28'>140</scene> (asn vs. <span style="color:blue">'''lys'''</span> ).  
Calculate along the chain, in the N to C-terminal direction how just several amino acid switches bring the positive net charge of whale myoglobin up to ''+4'' and elephants to ''+2'': (summing up the total charge of the protein) <scene name='52/523344/Elephantwhale/19'>residue position 8</scene> (<span style="color:red">'''glu'''</span> in elephents versus gln in whales), <scene name='52/523344/Elephantwhale/21'>12</scene> (<span style="color:blue">'''lys'''</span>  vs. <span style="color:lightblue">'''his'''</span>), <scene name='52/523344/Elephantwhale/22'>27</scene> (thr vs. <span style="color:red">'''asp'''</span>), <scene name='52/523344/Elephantwhale/23'>34</scene> (thr vs. <span style="color:blue">'''lys'''</span> ), <scene name='52/523344/Elephantwhale/24'>87</scene> (gln vs. <span style="color:blue">'''lys'''</span> ), <scene name='52/523344/Elephantwhale/26'>116</scene> (gln vs. <span style="color:lightblue">'''his'''</span>), <scene name='52/523344/Elephantwhale/27'>132</scene> (<span style="color:blue">'''lys'''</span>  vs. asn), <scene name='52/523344/Elephantwhale/28'>140</scene> (asn vs. <span style="color:blue">'''lys'''</span> ).  
*''note about illustration'': <span style="color:red">'''Asp and Glu'''</span> have a charge of ''-1'', <span style="color:blue">'''Arg and Lys'''</span> have a charge of ''+1'', <span style="color:lightblue">'''His'''</span> in the positions shown here - ''12'' and ''116'' (Table S2<ref name="whaleMyo" />) - have a charge of about ''+0.5''.
'''note about illustration''': <span style="color:red">'''Asp and Glu'''</span> have a charge of ''-1'', <span style="color:blue">'''Arg and Lys'''</span> have a charge of ''+1'', <span style="color:lightblue">'''His'''</span> in the positions shown here - ''12'' and ''116'' (Table S2<ref name="whaleMyo" />) - have a charge of about ''+0.5''.


Considering that the proteins in the Protein Data Bank have net charges that tend to fall between -10 and +10<ref>doi: 10.1073/pnas.0402797101</ref> , it may seem surprising that an increase of just +2 results in such a huge increase in solubility.  Consider though that many life processes, protein folding is a great example, exist in a near equilibrium state, where a relatively tiny change in enthalpy or entropy can push the system to one direction or the other.  In the case of solubility, where often the first dimer is neccessary to begin aggregation, a small bias away from forming dimers may be sufficient to prevent nucleation of aggragation, and hence increases the molecule's solubility.
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