Salt bridges
From Proteopedia
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A salt bridge is generally considered to exist when the centers of charge are 4 Å or less apart<ref>Jeffrey, George A., An introduction to hydrogen bonding, Oxford University Press, 1997. Page 192.</ref>. The center of charge of the arginine sidechain is the zeta carbon<ref name='GD'>PMID: 10449714</ref>. The energetic significance of such complementary charge pairs is a complex function of the local environment. | A salt bridge is generally considered to exist when the centers of charge are 4 Å or less apart<ref>Jeffrey, George A., An introduction to hydrogen bonding, Oxford University Press, 1997. Page 192.</ref>. The center of charge of the arginine sidechain is the zeta carbon<ref name='GD'>PMID: 10449714</ref>. The energetic significance of such complementary charge pairs is a complex function of the local environment. | ||
| - | + | Proteins from [[extremophiles|thermophiles]] have more salt bridges than do proteins from mesophiles<ref>PMID: 11793224</ref><ref>PMID: 11577980</ref>. These additional salt bridges contribute to stability, resisting denaturation by high temperature. | |
==Examples== | ==Examples== | ||
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===Ultraviolet-B receptor=== | ===Ultraviolet-B receptor=== | ||
UVR8 is an ultraviolet-B receptor in plants such as ''Arabidopsis''. It is a homodimer that, upon irradiation, dissociates into a monomer involved in transcriptional activation of UV protective proteins<ref>PMID:22388820</ref>. Unexpectedly, high ionic strength was found to dissociate the dimer. The homodimer [[4dnw]] contains many [[salt bridges]] and [[cation-pi interactions]] at the interface. [[Suggestions_for_new_articles#April:_Ultraviolet-B_Photoreceptor_Dimer_to_Monomer|More]]. | UVR8 is an ultraviolet-B receptor in plants such as ''Arabidopsis''. It is a homodimer that, upon irradiation, dissociates into a monomer involved in transcriptional activation of UV protective proteins<ref>PMID:22388820</ref>. Unexpectedly, high ionic strength was found to dissociate the dimer. The homodimer [[4dnw]] contains many [[salt bridges]] and [[cation-pi interactions]] at the interface. [[Suggestions_for_new_articles#April:_Ultraviolet-B_Photoreceptor_Dimer_to_Monomer|More]]. | ||
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| + | ==Visualization== | ||
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| + | Putative salt bridges can be displayed by [[FirstGlance in Jmol]]. | ||
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==References== | ==References== | ||
<references /> | <references /> | ||
Revision as of 18:15, 22 April 2012
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In proteins, salt bridges occur between amino acid side-chains with opposite positive or negative full-electron charges, namely, (at neutral pH) Glu- or Asp- vs. Arg+ or Lys+. They may also occur between ionized organic ligands, such as acetylcholine+ (or example at right: 1cbr), or inorganic ions, such as K+ or SO4=, and amino acid side-chains.
A salt bridge is generally considered to exist when the centers of charge are 4 Å or less apart[1]. The center of charge of the arginine sidechain is the zeta carbon[2]. The energetic significance of such complementary charge pairs is a complex function of the local environment.
Proteins from thermophiles have more salt bridges than do proteins from mesophiles[3][4]. These additional salt bridges contribute to stability, resisting denaturation by high temperature.
Contents |
Examples
Ultraviolet-B receptor
UVR8 is an ultraviolet-B receptor in plants such as Arabidopsis. It is a homodimer that, upon irradiation, dissociates into a monomer involved in transcriptional activation of UV protective proteins[5]. Unexpectedly, high ionic strength was found to dissociate the dimer. The homodimer 4dnw contains many salt bridges and cation-pi interactions at the interface. More.
Visualization
Putative salt bridges can be displayed by FirstGlance in Jmol.
References
- ↑ Jeffrey, George A., An introduction to hydrogen bonding, Oxford University Press, 1997. Page 192.
- ↑ Gallivan JP, Dougherty DA. Cation-pi interactions in structural biology. Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9459-64. PMID:10449714
- ↑ Das R, Gerstein M. The stability of thermophilic proteins: a study based on comprehensive genome comparison. Funct Integr Genomics. 2000 May;1(1):76-88. PMID:11793224 doi:10.1007/s101420000003
- ↑ Kumar S, Nussinov R. How do thermophilic proteins deal with heat? Cell Mol Life Sci. 2001 Aug;58(9):1216-33. PMID:11577980
- ↑ Wu D, Hu Q, Yan Z, Chen W, Yan C, Huang X, Zhang J, Yang P, Deng H, Wang J, Deng X, Shi Y. Structural basis of ultraviolet-B perception by UVR8. Nature. 2012 Feb 29;484(7393):214-9. doi: 10.1038/nature10931. PMID:22388820 doi:10.1038/nature10931
