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1jyk
From Proteopedia
(New page: 200px<br /><applet load="1jyk" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jyk, resolution 1.5Å" /> '''Catalytic Mechanism o...) |
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| - | [[Image:1jyk.gif|left|200px]]<br /><applet load="1jyk" size=" | + | [[Image:1jyk.gif|left|200px]]<br /><applet load="1jyk" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1jyk, resolution 1.5Å" /> | caption="1jyk, resolution 1.5Å" /> | ||
'''Catalytic Mechanism of CTP:phosphocholine Cytidylytransferase from Streptococcus pneumoniae (LicC)'''<br /> | '''Catalytic Mechanism of CTP:phosphocholine Cytidylytransferase from Streptococcus pneumoniae (LicC)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Pneumococcal LicC is a member of the nucleoside triphosphate transferase | + | Pneumococcal LicC is a member of the nucleoside triphosphate transferase superfamily and catalyzes the transfer of a cytidine monophosphate from CTP to phosphocholine to form CDP-choline. The structures of apo-LicC and the LicC-CDP-choline-Mg(2+) ternary complex were determined, and the comparison of these structures reveals a significant conformational change driven by the multivalent coordination of Mg(2+). The key event is breaking the Glu(216)-Arg(129) salt bridge, which triggers the coalescence of four individual beta-strands into two extended beta-sheets. These movements reorient the side chains of Trp(136) and Tyr(190) for the optimal binding and alignment of the phosphocholine moiety. Consistent with these conformational changes, LicC operates via a compulsory ordered kinetic mechanism. The structures explain the substrate specificity of LicC for CTP and phosphocholine and implicate a direct role for Mg(2+) in aligning phosphocholine for in-line nucleophilic attack and stabilizing the negative charge that develops in the pentacoordinate transition state. These results provide a structural basis for assigning a specific role for magnesium in the catalytic mechanism of pneumococcal LicC. |
==About this Structure== | ==About this Structure== | ||
| - | 1JYK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae]. Full crystallographic information is available from [http:// | + | 1JYK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptococcus_pneumoniae Streptococcus pneumoniae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JYK OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptococcus pneumoniae]] | [[Category: Streptococcus pneumoniae]] | ||
| - | [[Category: Kwak, B | + | [[Category: Kwak, B Y.]] |
| - | [[Category: Park, H | + | [[Category: Park, H w.]] |
[[Category: Yun, M.]] | [[Category: Yun, M.]] | ||
[[Category: 3d structure]] | [[Category: 3d structure]] | ||
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[[Category: licc]] | [[Category: licc]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:28:08 2008'' |
Revision as of 11:28, 21 February 2008
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Catalytic Mechanism of CTP:phosphocholine Cytidylytransferase from Streptococcus pneumoniae (LicC)
Overview
Pneumococcal LicC is a member of the nucleoside triphosphate transferase superfamily and catalyzes the transfer of a cytidine monophosphate from CTP to phosphocholine to form CDP-choline. The structures of apo-LicC and the LicC-CDP-choline-Mg(2+) ternary complex were determined, and the comparison of these structures reveals a significant conformational change driven by the multivalent coordination of Mg(2+). The key event is breaking the Glu(216)-Arg(129) salt bridge, which triggers the coalescence of four individual beta-strands into two extended beta-sheets. These movements reorient the side chains of Trp(136) and Tyr(190) for the optimal binding and alignment of the phosphocholine moiety. Consistent with these conformational changes, LicC operates via a compulsory ordered kinetic mechanism. The structures explain the substrate specificity of LicC for CTP and phosphocholine and implicate a direct role for Mg(2+) in aligning phosphocholine for in-line nucleophilic attack and stabilizing the negative charge that develops in the pentacoordinate transition state. These results provide a structural basis for assigning a specific role for magnesium in the catalytic mechanism of pneumococcal LicC.
About this Structure
1JYK is a Single protein structure of sequence from Streptococcus pneumoniae. Full crystallographic information is available from OCA.
Reference
Structure and mechanism of CTP:phosphocholine cytidylyltransferase (LicC) from Streptococcus pneumoniae., Kwak BY, Zhang YM, Yun M, Heath RJ, Rock CO, Jackowski S, Park HW, J Biol Chem. 2002 Feb 8;277(6):4343-50. Epub 2001 Nov 12. PMID:11706035
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