Triose Phosphate Isomerase Structure & Mechanism

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Triose phosphate isomerase (TIM)<ref>PMID:16511037</ref> (PDB [[1wyi]]) is a crucial enzyme in the glycolytic pathway. <scene name='Christian_Krenk_Sandbox/Nc_rainbow/1'>TIM</scene> reversibly converts the aldose Glyceraldehyde-3-phosphate (GASP) to the ketose Dihydroxyacetone phosphate (DHAP). The interconversion proceeds by an enediol intermediate.
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Triose phosphate isomerase (TIM)<ref>PMID:16511037</ref> (PDB [[1wyi]]) is a crucial enzyme in the glycolytic pathway. <scene name='Christian_Krenk_Sandbox/Nc_rainbow/1'>TIM</scene> reversibly converts the aldose Glyceraldehyde-3-phosphate (GAP) to the ketose Dihydroxyacetone phosphate (DHAP). The interconversion proceeds by an enediol intermediate.
==Structural Characteristics of TIM==
==Structural Characteristics of TIM==
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The secondary structure consists of 14 alpha helices and 8 beta sheets per monomer, making it fall in the SCOP category of alpha and beta proteins. <scene name='Christian_Krenk_Sandbox/Alpha_beta_barrel/2'>The tertiary structure is an alpha-beta barrel.
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The secondary structure consists of 14 alpha helices and 8 beta sheets per monomer, making it fall in the SCOP category of alpha and beta proteins. The tertiary structure is a <scene name='Christian_Krenk_Sandbox/Alpha_beta_barrel/2'>alpha-beta barrel.</scene>
The quaternary structure is a homodimer.
The quaternary structure is a homodimer.

Revision as of 20:18, 1 March 2010

Contents

Triose Phosphate Isomerase (TIM)

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Triose phosphate isomerase (TIM)[1] (PDB 1wyi) is a crucial enzyme in the glycolytic pathway. reversibly converts the aldose Glyceraldehyde-3-phosphate (GAP) to the ketose Dihydroxyacetone phosphate (DHAP). The interconversion proceeds by an enediol intermediate.

Structural Characteristics of TIM

The secondary structure consists of 14 alpha helices and 8 beta sheets per monomer, making it fall in the SCOP category of alpha and beta proteins. The tertiary structure is a The quaternary structure is a homodimer.


Mechanism of TIM

The enzyme aids in catalysis by binding tightly to the enediol transition state. To convert GAP to the enediol intermediate, a proton is abstracted from C2 by a base and the carbonyl oxygen atom is protonated by an acid. To convert the enediol intermediate to DHAP, C1 is protonated by Glu 165, with His 95 removing a proton from C2’s OH group. As a result, the catalytic groups are back at their original states, and catalysis is completed.

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PDB ID 1wyi

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1wyi, resolution 2.20Å ()
Activity: Triose-phosphate isomerase, with EC number 5.3.1.1
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml



PDB ID 1hti

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1hti, resolution 2.80Å ()
Ligands:
Activity: Triose-phosphate isomerase, with EC number 5.3.1.1
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml



References

  1. Kinoshita T, Maruki R, Warizaya M, Nakajima H, Nishimura S. Structure of a high-resolution crystal form of human triosephosphate isomerase: improvement of crystals using the gel-tube method. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2005 Apr 1;61(Pt, 4):346-9. Epub 2005 Mar 24. PMID:16511037 doi:10.1107/S1744309105008341
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