1zdr
From Proteopedia
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|PDB= 1zdr |SIZE=350|CAPTION= <scene name='initialview01'>1zdr</scene>, resolution 2.0Å | |PDB= 1zdr |SIZE=350|CAPTION= <scene name='initialview01'>1zdr</scene>, resolution 2.0Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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] | + | |ACTIVITY= <span class='plainlinks'>[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] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1zdr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1zdr OCA], [http://www.ebi.ac.uk/pdbsum/1zdr PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1zdr RCSB]</span> | ||
}} | }} | ||
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[[Category: Lee, S Y.]] | [[Category: Lee, S Y.]] | ||
[[Category: Wemmer, D.]] | [[Category: Wemmer, D.]] | ||
| - | [[Category: GOL]] | ||
| - | [[Category: SO4]] | ||
[[Category: dhfr]] | [[Category: dhfr]] | ||
[[Category: nadp]] | [[Category: nadp]] | ||
[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 01:34:33 2008'' |
Revision as of 22:34, 30 March 2008
| |||||||
| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Activity: | Dihydrofolate reductase, with EC number 1.5.1.3 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| 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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