This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2zf5
From Proteopedia
OCA (Talk | contribs)
(New page: 200px <!-- The line below this paragraph, containing "STRUCTURE_2zf5", creates the "Structure Box" on the page. You may change the PDB parameter (which sets the PD...)
Next diff →
Revision as of 05:51, 7 May 2008
Crystal Structure of highly thermostable glycerol kinase from a hyperthermophilic archaeon
Overview
The crystal structure of glycerol kinase from the hyperthermophilic archaeon Thermococcus kodakaraensis (Tk-GK) in a dimeric form was determined at a resolution of 2.4 A. This is the first crystal structure of a hyperthermophilic glycerol kinase. The overall structure of the Tk-GK dimer is very similar to that of the Escherichia coli glycerol kinase (Ec-GK) dimer. However, two dimers of Ec-GK can associate into a tetramer with a twofold axis, whereas those of Tk-GK cannot. This may be the reason why Tk-GK is not inhibited by fructose 1,6-bisphosphate, because the fructose 1,6-bisphosphate binding site is produced only when a tetrameric structure is formed. Differential scanning calorimetry analyses indicate that Tk-GK is a highly thermostable protein with a melting temperature (T(m)) of 105.4 degrees C for the major transition. This value is higher than that of Ec-GK by 34.1 degrees C. Comparison of the crystal structures of Tk-GK and Ec-GK indicate that there is a marked difference in the number of ion pairs in the alpha16 helix. Four ion pairs, termed IP1-IP4, are formed in this helix in the Tk-GK structure. To examine whether these ion pairs contribute to the stabilization of Tk-GK, four Tk-GK and four Ec-GK derivatives with reciprocal mutations at the IP1-IP4 sites were constructed. The determination of their stabilities indicates that the removal of each ion pair does not affect the stability of Tk-GK significantly, whereas the mutations designed to introduce one of these ion pairs stabilize or destabilize Ec-GK considerably. These results suggest that the ion pairs in the alpha16 helix contribute to the stabilization of Tk-GK in a cooperative manner.
About this Structure
2ZF5 is a Single protein structure of sequence from Thermococcus kodakarensis. Full crystallographic information is available from OCA.
Reference
Crystal structure of highly thermostable glycerol kinase from a hyperthermophilic archaeon in a dimeric form., Koga Y, Katsumi R, You DJ, Matsumura H, Takano K, Kanaya S, FEBS J. 2008 May;275(10):2632-43. Epub 2008 Apr 17. PMID:18422647 Page seeded by OCA on Wed May 7 08:51:17 2008
