1kht
From Proteopedia
(New page: 200px<br /><applet load="1kht" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kht, resolution 2.50Å" /> '''Adenylate kinase fro...) |
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| - | [[Image:1kht.jpg|left|200px]]<br /><applet load="1kht" size=" | + | [[Image:1kht.jpg|left|200px]]<br /><applet load="1kht" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1kht, resolution 2.50Å" /> | caption="1kht, resolution 2.50Å" /> | ||
'''Adenylate kinase from Methanococcus voltae'''<br /> | '''Adenylate kinase from Methanococcus voltae'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structures of adenylate kinases from the thermophile | + | The crystal structures of adenylate kinases from the thermophile Methanococcus thermolithotrophicus and the mesophile Methanococcus voltae have been solved to resolutions of 2.8A and 2.5A, respectively. The structures of the enzymes are similar to that of the adenylate kinase from archaeal Sulfolobus acidocaldarius in many respects such as the extended central beta-sheets, the short LID domain, and the trimeric state. The analysis of unligated and AMP-bound subunits of M.voltae suggests that movements of two mobile domains are not independent of each other. The methanococcal structures are examined with respect to their lack of the "invariant" Lys residue within the phosphate-binding loop, and two Arg residues in the LID domain are proposed as substituting residues based on their conservation among archaeal adenylate kinases and mobility within the structures. Since S.acidocaldarius adenylate kinase has the invariant Lys residue as well as the two Arg residues, its phosphate-binding loop is examined and compared with those of other adenylate kinases. On the basis of the comparison and other available biochemical data, the unusual conformation of the Lys residue in S.acidocaldarius adenylate kinase is explained. Despite possessing 78% sequence identity, the methanococcal enzymes exhibit significantly different thermal stabilities. To study the determinants of thermostability, several structural features including salt-links, hydrogen bonds, packing density, surface to volume ratio and buried surface area are compared between the enzymes. From their difference in apolar buried surface area, hydrophobic interaction is proposed to be a basis for the disparate thermostabilities, and the corresponding free energy difference is also estimated. Results of previous mutational studies are interpreted in terms of the crystal structures, and support the importance of hydrophobic interactions in thermostability. |
==About this Structure== | ==About this Structure== | ||
| - | 1KHT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanococcus_voltae Methanococcus voltae] with AMP as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Adenylate_kinase Adenylate kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.4.3 2.7.4.3] Full crystallographic information is available from [http:// | + | 1KHT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanococcus_voltae Methanococcus voltae] with <scene name='pdbligand=AMP:'>AMP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Adenylate_kinase Adenylate kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.4.3 2.7.4.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KHT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Methanococcus voltae]] | [[Category: Methanococcus voltae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Criswell, A | + | [[Category: Criswell, A R.]] |
| - | [[Category: Jr., G | + | [[Category: Jr., G N.Phillips.]] |
[[Category: Konisky, J.]] | [[Category: Konisky, J.]] | ||
[[Category: AMP]] | [[Category: AMP]] | ||
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[[Category: phosphotransferase]] | [[Category: phosphotransferase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:34:20 2008'' |
Revision as of 11:34, 21 February 2008
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Adenylate kinase from Methanococcus voltae
Overview
The crystal structures of adenylate kinases from the thermophile Methanococcus thermolithotrophicus and the mesophile Methanococcus voltae have been solved to resolutions of 2.8A and 2.5A, respectively. The structures of the enzymes are similar to that of the adenylate kinase from archaeal Sulfolobus acidocaldarius in many respects such as the extended central beta-sheets, the short LID domain, and the trimeric state. The analysis of unligated and AMP-bound subunits of M.voltae suggests that movements of two mobile domains are not independent of each other. The methanococcal structures are examined with respect to their lack of the "invariant" Lys residue within the phosphate-binding loop, and two Arg residues in the LID domain are proposed as substituting residues based on their conservation among archaeal adenylate kinases and mobility within the structures. Since S.acidocaldarius adenylate kinase has the invariant Lys residue as well as the two Arg residues, its phosphate-binding loop is examined and compared with those of other adenylate kinases. On the basis of the comparison and other available biochemical data, the unusual conformation of the Lys residue in S.acidocaldarius adenylate kinase is explained. Despite possessing 78% sequence identity, the methanococcal enzymes exhibit significantly different thermal stabilities. To study the determinants of thermostability, several structural features including salt-links, hydrogen bonds, packing density, surface to volume ratio and buried surface area are compared between the enzymes. From their difference in apolar buried surface area, hydrophobic interaction is proposed to be a basis for the disparate thermostabilities, and the corresponding free energy difference is also estimated. Results of previous mutational studies are interpreted in terms of the crystal structures, and support the importance of hydrophobic interactions in thermostability.
About this Structure
1KHT is a Single protein structure of sequence from Methanococcus voltae with as ligand. Active as Adenylate kinase, with EC number 2.7.4.3 Full crystallographic information is available from OCA.
Reference
Structures of thermophilic and mesophilic adenylate kinases from the genus Methanococcus., Criswell AR, Bae E, Stec B, Konisky J, Phillips GN Jr, J Mol Biol. 2003 Jul 25;330(5):1087-99. PMID:12860130
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