1zdr
From Proteopedia
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| - | [[Image:1zdr.gif|left|200px]] | + | [[Image:1zdr.gif|left|200px]] |
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| - | '''DHFR from Bacillus Stearothermophilus''' | + | {{Structure |
| + | |PDB= 1zdr |SIZE=350|CAPTION= <scene name='initialview01'>1zdr</scene>, resolution 2.0Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> and <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene> | ||
| + | |ACTIVITY= [http://en.wikipedia.org/wiki/Dihydrofolate_reductase Dihydrofolate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.5.1.3 1.5.1.3] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''DHFR from Bacillus Stearothermophilus''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1ZDR is a [ | + | 1ZDR is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Geobacillus_stearothermophilus Geobacillus stearothermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZDR OCA]. |
==Reference== | ==Reference== | ||
| - | Structure and hydride transfer mechanism of a moderate thermophilic dihydrofolate reductase from Bacillus stearothermophilus and comparison to its mesophilic and hyperthermophilic homologues., Kim HS, Damo SM, Lee SY, Wemmer D, Klinman JP, Biochemistry. 2005 Aug 30;44(34):11428-39. PMID:[http:// | + | Structure and hydride transfer mechanism of a moderate thermophilic dihydrofolate reductase from Bacillus stearothermophilus and comparison to its mesophilic and hyperthermophilic homologues., Kim HS, Damo SM, Lee SY, Wemmer D, Klinman JP, Biochemistry. 2005 Aug 30;44(34):11428-39. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16114879 16114879] |
[[Category: Dihydrofolate reductase]] | [[Category: Dihydrofolate reductase]] | ||
[[Category: Geobacillus stearothermophilus]] | [[Category: Geobacillus stearothermophilus]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 15:34:15 2008'' |
Revision as of 13:34, 20 March 2008
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| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Activity: | Dihydrofolate reductase, with EC number 1.5.1.3 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
DHFR from Bacillus Stearothermophilus
Overview
Dihydrofolate reductase (DHFR) from a moderate thermophilic organism, Bacillus stearothermophilus, has been cloned and expressed. Physical characterization of the protein (BsDHFR) indicates that it is a monomeric protein with a molecular mass of 18,694.6 Da (0.8), coincident with the mass of 18 694.67 Da calculated from the primary sequence. Determination of the X-ray structure of BsDHFR provides the first structure for a monomeric DHFR from a thermophilic organism, indicating a high degree of conservation of structure in relation to all chromosomal DHFRs. Structurally based sequence alignment of DHFRs indicates the following levels of sequence identity and similarity for BsDHFR: 38 and 58% with Escherichia coli, 35 and 56% with Lactobacillus casei, and 23 and 40% with Thermotoga maritima, respectively. Steady state kinetic isotope effect studies indicate an ordered kinetic mechanism at elevated temperatures, with NADPH binding first to the enzyme. This converts to a more random mechanism at reduced temperatures, reflected in a greatly reduced K(m) for dihydrofolate at 20 degrees C in relation to that at 60 degrees C. A reduction in either temperature or pH reduces the degree to which the hydride transfer step is rate-determining for the second-order reaction of DHF with the enzyme-NADPH binary complex. Transient state kinetics have been used to study the temperature dependence of the isotope effect on hydride transfer at pH 9 between 10 and 50 degrees C. The data support rate-limiting hydride transfer with a moderate enthalpy of activation (E(a) = 5.5 kcal/mol) and a somewhat greater temperature dependence for the kinetic isotope effect than predicted from classical behavior [A(H)/A(D) = 0.57 (0.15)]. Comparison of kinetic parameters for BsDHFR to published data for DHFR from E. coli and T. maritima shows a decreasing trend in efficiency of hydride transfer with increasing thermophilicity of the protein. These results are discussed in the context of the capacity of each enzyme to optimize H-tunneling from donor (NADPH) to acceptor (DHF) substrates.
About this Structure
1ZDR is a Protein complex structure of sequences from Geobacillus stearothermophilus. Full crystallographic information is available from OCA.
Reference
Structure and hydride transfer mechanism of a moderate thermophilic dihydrofolate reductase from Bacillus stearothermophilus and comparison to its mesophilic and hyperthermophilic homologues., Kim HS, Damo SM, Lee SY, Wemmer D, Klinman JP, Biochemistry. 2005 Aug 30;44(34):11428-39. PMID:16114879
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