1fcb: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1fcb.gif|left|200px]] | [[Image:1fcb.gif|left|200px]] | ||
'''MOLECULAR STRUCTURE OF FLAVOCYTOCHROME B2 AT 2.4 ANGSTROMS RESOLUTION''' | {{Structure | ||
|PDB= 1fcb |SIZE=350|CAPTION= <scene name='initialview01'>1fcb</scene>, resolution 2.4Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</scene> and <scene name='pdbligand=PYR:PYRUVIC ACID'>PYR</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/L-lactate_dehydrogenase_(cytochrome) L-lactate dehydrogenase (cytochrome)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.2.3 1.1.2.3] | |||
|GENE= | |||
}} | |||
'''MOLECULAR STRUCTURE OF FLAVOCYTOCHROME B2 AT 2.4 ANGSTROMS RESOLUTION''' | |||
==Overview== | ==Overview== | ||
| Line 7: | Line 16: | ||
==About this Structure== | ==About this Structure== | ||
1FCB is a [ | 1FCB is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FCB OCA]. | ||
==Reference== | ==Reference== | ||
Molecular structure of flavocytochrome b2 at 2.4 A resolution., Xia ZX, Mathews FS, J Mol Biol. 1990 Apr 20;212(4):837-63. PMID:[http:// | Molecular structure of flavocytochrome b2 at 2.4 A resolution., Xia ZX, Mathews FS, J Mol Biol. 1990 Apr 20;212(4):837-63. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/2329585 2329585] | ||
[[Category: L-lactate dehydrogenase (cytochrome)]] | [[Category: L-lactate dehydrogenase (cytochrome)]] | ||
[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
| Line 21: | Line 30: | ||
[[Category: oxidoreductase (ch-oh(d)-cytochrome(a))]] | [[Category: oxidoreductase (ch-oh(d)-cytochrome(a))]] | ||
''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 11:07:17 2008'' | ||
Revision as of 12:07, 20 March 2008
| |||||||
| , resolution 2.4Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , and | ||||||
| Activity: | L-lactate dehydrogenase (cytochrome), with EC number 1.1.2.3 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
MOLECULAR STRUCTURE OF FLAVOCYTOCHROME B2 AT 2.4 ANGSTROMS RESOLUTION
OverviewOverview
The crystal structure of flavocytochrome b2 has been solved at 3.0 A resolution by the method of multiple isomorphous replacement with anomalous scattering. Area detector data from native and two heavy-atom derivative crystals were used. The phases were refined by the B.C. Wang phase-filtering procedure utilizing the 67% (v/v) solvent content of the crystals. A molecular model was built first on a minimap and then on computer graphics from a combination of maps both averaged and not averaged about the molecular symmetry axis. The structure was extended to 2.4 A resolution using film data recorded at a synchrotron and refined by the Hendrickson-Konnert procedure. The molecule, a tetramer of Mr 230,000, is located on a crystallographic 2-fold axis and possesses local 4-fold symmetry. Each subunit is composed of two domains, one binding a heme and the other an FMN prosthetic group. In subunit 1, both the cystochrome and the flavin-binding domain are visible in the electron density map. In subunit 2 the cytochrome domain is disordered. However, in the latter, a molecule of pyruvate, the product of the enzymatic reaction, is bound at the active site. The cytochrome domain consists of residues 1 to 99 and is folded in a fashion similar to the homologous soluble fragment of cytochrome b5. The flavin binding domain contains a parallel beta 8 alpha 8 barrel structure and is composed of residues 100 to 486. The remaining 25 residues form a tail that wraps around the molecular 4-fold axis and is in contact with each remaining subunit. The FMN moiety, which is located at the C-terminal end of the central beta-barrel, is mostly sequestered from solvent; it forms hydrogen bond interactions with main- and side-chain atoms from six of the eight beta-strands. The interaction of Lys349 with atoms N-1 and O-2 of the flavin ring is probably responsible for stabilization of the anionic form of the flavin semiquinone and hydroquinone and enhancing the reactivity of atom N-5 toward sulfite. The binding of pyruvate at the active site in subunit 2 is stabilized by interaction of its carboxylate group with the side-chain atoms of Arg376 and Tyr143. Residues His373 and Tyr254 interact with the keto-oxygen atom and are involved in catalysis. In contrast, four water molecules occupy the substrate-binding site in subunit 1 and Tyr143 forms a hydrogen bond to the ordered heme propionate group. Otherwise the two flavin-binding domains are identical within experimental error.(ABSTRACT TRUNCATED AT 400 WORDS)
About this StructureAbout this Structure
1FCB is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
ReferenceReference
Molecular structure of flavocytochrome b2 at 2.4 A resolution., Xia ZX, Mathews FS, J Mol Biol. 1990 Apr 20;212(4):837-63. PMID:2329585
Page seeded by OCA on Thu Mar 20 11:07:17 2008