1u7d: Difference between revisions
New page: left|200px<br /><applet load="1u7d" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u7d, resolution 2.65Å" /> '''crystal structure of... |
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[[Image:1u7d.gif|left|200px]]<br /><applet load="1u7d" size=" | [[Image:1u7d.gif|left|200px]]<br /><applet load="1u7d" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1u7d, resolution 2.65Å" /> | caption="1u7d, resolution 2.65Å" /> | ||
'''crystal structure of apo M. jannashii tyrosyl-tRNA synthetase'''<br /> | '''crystal structure of apo M. jannashii tyrosyl-tRNA synthetase'''<br /> | ||
==Overview== | ==Overview== | ||
The Methanococcus jannaschii tRNA(Tyr)/TyrRS pair has been engineered to | The Methanococcus jannaschii tRNA(Tyr)/TyrRS pair has been engineered to incorporate unnatural amino acids into proteins in E. coli. To reveal the structural basis for the altered specificity of mutant TyrRS for O-methyl-L-tyrosine (OMeTyr), the crystal structures for the apo wild-type and mutant M. jannaschii TyrRS were determined at 2.66 and 3.0 A, respectively, for comparison with the published structure of TyrRS complexed with tRNA(Tyr) and substrate tyrosine. A large conformational change was found for the anticodon recognition loop 257-263 of wild-type TyrRS upon tRNA binding in order to facilitate recognition of G34 of the anticodon loop through pi-stacking and hydrogen bonding interactions. Loop 133-143, which is close to the tRNA acceptor stem-binding site, also appears to be stabilized by interaction with the tRNA(Tyr). Binding of the substrate tyrosine results in subtle and cooperative movements of the side chains within the tyrosine-binding pocket. In the OMeTyr-specific mutant synthetase structure, the signature motif KMSKS loop and acceptor stem-binding loop 133-143 were surprisingly ordered in the absence of bound ATP and tRNA. The active-site mutations result in altered hydrogen bonding and steric interactions which favor binding of OMeTyr over L-tyrosine. The structure of the mutant and wild-type TyrRS now provide a basis for generating new active-site libraries to evolve synthetases specific for other unnatural amino acids. | ||
==About this Structure== | ==About this Structure== | ||
1U7D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii]. Active as [http://en.wikipedia.org/wiki/Tyrosine--tRNA_ligase Tyrosine--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.1 6.1.1.1] Full crystallographic information is available from [http:// | 1U7D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii]. Active as [http://en.wikipedia.org/wiki/Tyrosine--tRNA_ligase Tyrosine--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.1 6.1.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1U7D OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Tyrosine--tRNA ligase]] | [[Category: Tyrosine--tRNA ligase]] | ||
[[Category: Schultz, P | [[Category: Schultz, P G.]] | ||
[[Category: Wang, L.]] | [[Category: Wang, L.]] | ||
[[Category: Wilson, I | [[Category: Wilson, I A.]] | ||
[[Category: Zhang, Y.]] | [[Category: Zhang, Y.]] | ||
[[Category: rossmann fold]] | [[Category: rossmann fold]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:21:27 2008'' | ||
Revision as of 16:21, 21 February 2008
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crystal structure of apo M. jannashii tyrosyl-tRNA synthetase
OverviewOverview
The Methanococcus jannaschii tRNA(Tyr)/TyrRS pair has been engineered to incorporate unnatural amino acids into proteins in E. coli. To reveal the structural basis for the altered specificity of mutant TyrRS for O-methyl-L-tyrosine (OMeTyr), the crystal structures for the apo wild-type and mutant M. jannaschii TyrRS were determined at 2.66 and 3.0 A, respectively, for comparison with the published structure of TyrRS complexed with tRNA(Tyr) and substrate tyrosine. A large conformational change was found for the anticodon recognition loop 257-263 of wild-type TyrRS upon tRNA binding in order to facilitate recognition of G34 of the anticodon loop through pi-stacking and hydrogen bonding interactions. Loop 133-143, which is close to the tRNA acceptor stem-binding site, also appears to be stabilized by interaction with the tRNA(Tyr). Binding of the substrate tyrosine results in subtle and cooperative movements of the side chains within the tyrosine-binding pocket. In the OMeTyr-specific mutant synthetase structure, the signature motif KMSKS loop and acceptor stem-binding loop 133-143 were surprisingly ordered in the absence of bound ATP and tRNA. The active-site mutations result in altered hydrogen bonding and steric interactions which favor binding of OMeTyr over L-tyrosine. The structure of the mutant and wild-type TyrRS now provide a basis for generating new active-site libraries to evolve synthetases specific for other unnatural amino acids.
About this StructureAbout this Structure
1U7D is a Single protein structure of sequence from Methanocaldococcus jannaschii. Active as Tyrosine--tRNA ligase, with EC number 6.1.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of apo wild-type M. jannaschii tyrosyl-tRNA synthetase (TyrRS) and an engineered TyrRS specific for O-methyl-L-tyrosine., Zhang Y, Wang L, Schultz PG, Wilson IA, Protein Sci. 2005 May;14(5):1340-9. PMID:15840835
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