Extremophile
From Proteopedia
(Difference between revisions)
| Line 8: | Line 8: | ||
Whales and elephants are both large animals that take life slow - walking slow, singing slow.. But whales swim underwater while holding their breaths for long periods of time, and elephants can not: ''Why can whales hold their breaths for long, and elephants can not?'' One clue to this discrepancy is the difference in concentrations of <scene name='55/557585/Align_test/5'>myoglobin</scene> in whale and elephant muscle tissue: ''More myoglobin means more oxygen storage capacity'', and whales have over ''15 times'' the concentration of myoglobin as elephants do (''70 mg/g'' wet mass compared to the elephants ''4.6''). But this leads to a biophysical question. | Whales and elephants are both large animals that take life slow - walking slow, singing slow.. But whales swim underwater while holding their breaths for long periods of time, and elephants can not: ''Why can whales hold their breaths for long, and elephants can not?'' One clue to this discrepancy is the difference in concentrations of <scene name='55/557585/Align_test/5'>myoglobin</scene> in whale and elephant muscle tissue: ''More myoglobin means more oxygen storage capacity'', and whales have over ''15 times'' the concentration of myoglobin as elephants do (''70 mg/g'' wet mass compared to the elephants ''4.6''). But this leads to a biophysical question. | ||
| - | A very high concentration of myoglobin should lead to aggregation, which would prevent myoglobin from functioning, so ''how do whales' myoglobin deal with this extreme demand, and why can't elephants' myoglobin accumulate to high concentrations as well?'' In a recent article in the journal Science<ref>DOI:10.1126/science.1234192</ref>, the laboratories of Professors Berenbrink, Campbell, and Cossins demonstrate that ''natural variation in net positive charge explains aquatic and terrestrial animals' different diving abilities''. Following this pattern, whale myoglobin has a net charge ''two formal charges higher'' than in elephants: ''+4 compared to +2'' in the elephant. Apparently a protein's solubility is a function of its net charge<ref> | + | A very high concentration of myoglobin should lead to aggregation, which would prevent myoglobin from functioning, so ''how do whales' myoglobin deal with this extreme demand, and why can't elephants' myoglobin accumulate to high concentrations as well?'' In a recent article in the journal Science<ref name="whaleMyo"> DOI:10.1126/science.1234192</ref>, the laboratories of Professors Berenbrink, Campbell, and Cossins demonstrate that ''natural variation in net positive charge explains aquatic and terrestrial animals' different diving abilities''. Following this pattern, whale myoglobin has a net charge ''two formal charges higher'' than in elephants: ''+4 compared to +2'' in the elephant. Apparently a protein's solubility is a function of its net charge<ref>PMID: 14741208 </ref>, where ''a protein with a higher net charge is much more soluble''. |
It comes down to <scene name='55/557585/Align_test/18'>eight divergent amino acids (elephant's amino acids in yellow halos)</scene>. Without these amino acids, myoglobin in both whale and elephants has a charge of ''+1''. 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'': <scene name='52/523344/Elephantwhale/19'>residue position 8</scene>, <scene name='52/523344/Elephantwhale/21'>12</scene>, <scene name='52/523344/Elephantwhale/22'>27</scene>, <scene name='52/523344/Elephantwhale/23'>34</scene>, <scene name='52/523344/Elephantwhale/24'>87</scene>, <scene name='52/523344/Elephantwhale/26'>116</scene>, <scene name='52/523344/Elephantwhale/27'>132</scene>, <scene name='52/523344/Elephantwhale/28'>140</scene>. | It comes down to <scene name='55/557585/Align_test/18'>eight divergent amino acids (elephant's amino acids in yellow halos)</scene>. Without these amino acids, myoglobin in both whale and elephants has a charge of ''+1''. 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'': <scene name='52/523344/Elephantwhale/19'>residue position 8</scene>, <scene name='52/523344/Elephantwhale/21'>12</scene>, <scene name='52/523344/Elephantwhale/22'>27</scene>, <scene name='52/523344/Elephantwhale/23'>34</scene>, <scene name='52/523344/Elephantwhale/24'>87</scene>, <scene name='52/523344/Elephantwhale/26'>116</scene>, <scene name='52/523344/Elephantwhale/27'>132</scene>, <scene name='52/523344/Elephantwhale/28'>140</scene>. | ||
| - | *<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 | + | *<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''. |
<!-- | <!-- | ||
Revision as of 19:22, 5 December 2013
| |||||||||||
- ↑ 1.0 1.1 Mirceta S, Signore AV, Burns JM, Cossins AR, Campbell KL, Berenbrink M. Evolution of mammalian diving capacity traced by myoglobin net surface charge. Science. 2013 Jun 14;340(6138):1234192. doi: 10.1126/science.1234192. PMID:23766330 doi:http://dx.doi.org/10.1126/science.1234192
- ↑ Goh CS, Lan N, Douglas SM, Wu B, Echols N, Smith A, Milburn D, Montelione GT, Zhao H, Gerstein M. Mining the structural genomics pipeline: identification of protein properties that affect high-throughput experimental analysis. J Mol Biol. 2004 Feb 6;336(1):115-30. PMID:14741208 doi:http://dx.doi.org/10.1016/S0022283603014748
Proteopedia Page Contributors and Editors (what is this?)
Joseph M. Steinberger, Joel L. Sussman, Alexander Berchansky, Michal Harel
