1nsj
From Proteopedia
(New page: 200px<br /><applet load="1nsj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nsj, resolution 2.0Å" /> '''CRYSTAL STRUCTURE OF ...) |
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| - | [[Image:1nsj.gif|left|200px]]<br /><applet load="1nsj" size=" | + | [[Image:1nsj.gif|left|200px]]<br /><applet load="1nsj" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1nsj, resolution 2.0Å" /> | caption="1nsj, resolution 2.0Å" /> | ||
'''CRYSTAL STRUCTURE OF PHOSPHORIBOSYL ANTHRANILATE ISOMERASE FROM THERMOTOGA MARITIMA'''<br /> | '''CRYSTAL STRUCTURE OF PHOSPHORIBOSYL ANTHRANILATE ISOMERASE FROM THERMOTOGA MARITIMA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structural basis of thermostability of proteins is of great scientific | + | The structural basis of thermostability of proteins is of great scientific and biotechnological interest. Differences in the X-ray structues of orthologous proteins from hyperthermophilic and mesophilic organisms can indicate crucial stabilizing interactions. To this end the crystal structure of dimeric phosphoribosyl anthranilate isomerase from the hyperthermophile Thermotoga maritima (tPRAI) was determined using phases derived from the isomorphous replacement method and was refined at 2.0 A resolution. The comparison to the known 2.0 A structure of PRAI from Escherichia coli (ePRAI) shows that tPRAI has the complete TIM- or (beta alpha)8-barrel fold, whereas helix alpha5 in ePRAI is replaced by a loop. The subunits of tPRAI associate via the N-terminal faces of their central beta-barrels. Two long, symmetry-related loops that protrude reciprocally into cavities of the other subunit provide for multiple hydrophobic interactions. Moreover, the side chains of the N-terminal methionines and the C-terminal leucines of both subunits are immobilized in a hydrophobic cluster, and the number of salt bridges is increased in tPRAI. These features appear to be mainly responsible for the high thermostability of tPRAI. In contrast to other hyperthermostable enzymes, tPRAI at 25 degrees C is catalytically more efficient than ePRAI, mainly due to its small K(M) value for the substrate [Sterner, R., Kleemann, G. R., Szadkowski, H., Lustig, A., Hennig, M., & Kirschner, K. (1996) Protein Sci. 5, 2000-2008]. The increased number of hydrogen bonds between the phosphate ion and tPRAI compared to ePRAI could be responsible for this effect. |
==About this Structure== | ==About this Structure== | ||
| - | 1NSJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with PO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phosphoribosylanthranilate_isomerase Phosphoribosylanthranilate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.24 5.3.1.24] Full crystallographic information is available from [http:// | + | 1NSJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phosphoribosylanthranilate_isomerase Phosphoribosylanthranilate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.24 5.3.1.24] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NSJ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Thermotoga maritima]] | [[Category: Thermotoga maritima]] | ||
[[Category: Hennig, M.]] | [[Category: Hennig, M.]] | ||
| - | [[Category: Jansonius, J | + | [[Category: Jansonius, J N.J.]] |
[[Category: PO4]] | [[Category: PO4]] | ||
[[Category: isomerase]] | [[Category: isomerase]] | ||
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[[Category: thermostability]] | [[Category: thermostability]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:09:32 2008'' |
Revision as of 12:09, 21 February 2008
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CRYSTAL STRUCTURE OF PHOSPHORIBOSYL ANTHRANILATE ISOMERASE FROM THERMOTOGA MARITIMA
Overview
The structural basis of thermostability of proteins is of great scientific and biotechnological interest. Differences in the X-ray structues of orthologous proteins from hyperthermophilic and mesophilic organisms can indicate crucial stabilizing interactions. To this end the crystal structure of dimeric phosphoribosyl anthranilate isomerase from the hyperthermophile Thermotoga maritima (tPRAI) was determined using phases derived from the isomorphous replacement method and was refined at 2.0 A resolution. The comparison to the known 2.0 A structure of PRAI from Escherichia coli (ePRAI) shows that tPRAI has the complete TIM- or (beta alpha)8-barrel fold, whereas helix alpha5 in ePRAI is replaced by a loop. The subunits of tPRAI associate via the N-terminal faces of their central beta-barrels. Two long, symmetry-related loops that protrude reciprocally into cavities of the other subunit provide for multiple hydrophobic interactions. Moreover, the side chains of the N-terminal methionines and the C-terminal leucines of both subunits are immobilized in a hydrophobic cluster, and the number of salt bridges is increased in tPRAI. These features appear to be mainly responsible for the high thermostability of tPRAI. In contrast to other hyperthermostable enzymes, tPRAI at 25 degrees C is catalytically more efficient than ePRAI, mainly due to its small K(M) value for the substrate [Sterner, R., Kleemann, G. R., Szadkowski, H., Lustig, A., Hennig, M., & Kirschner, K. (1996) Protein Sci. 5, 2000-2008]. The increased number of hydrogen bonds between the phosphate ion and tPRAI compared to ePRAI could be responsible for this effect.
About this Structure
1NSJ is a Single protein structure of sequence from Thermotoga maritima with as ligand. Active as Phosphoribosylanthranilate isomerase, with EC number 5.3.1.24 Full crystallographic information is available from OCA.
Reference
Crystal structure at 2.0 A resolution of phosphoribosyl anthranilate isomerase from the hyperthermophile Thermotoga maritima: possible determinants of protein stability., Hennig M, Sterner R, Kirschner K, Jansonius JN, Biochemistry. 1997 May 20;36(20):6009-16. PMID:9166771
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