1FCB

MOLECULAR STRUCTURE OF FLAVOCYTOCHROME B2 AT 2.4 ANGSTROMS RESOLUTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Observed: 0.188 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Molecular structure of flavocytochrome b2 at 2.4 A resolution.

Xia, Z.X.Mathews, F.S.

(1990) J Mol Biol 212: 837-863

  • DOI: 10.1016/0022-2836(90)90240-M
  • Primary Citation of Related Structures:  
    1FCB

  • PubMed Abstract: 
  • 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 w ...

    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)


    Related Citations: 
    • Three-Dimensional Structure of Flavocytochrome B2 from Baker,S Yeast at 3.0-Angstroms Resolution
      Xia, Z.-X., Shamala, N., Bethge, P.H., Lim, L.W., Bellamy, H.D., Xuong, N.H., Lederer, F., Mathews, F.S.
      (1987) Proc Natl Acad Sci U S A 84: 2629
    • Crystallographic Study of Bakers, Yeast Cytochrome B2
      Mathews, F.S., Lederer, F.
      (1976) J Mol Biol 102: 853

    Organizational Affiliation

    Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
FLAVOCYTOCHROME B2AB511Saccharomyces cerevisiaeMutation(s): 0 
EC: 1.1.2.3
Find proteins for P00175 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore P00175 
Go to UniProtKB:  P00175
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
FMN
Query on FMN

Download CCD File 
A, B
FLAVIN MONONUCLEOTIDE
C17 H21 N4 O9 P
FVTCRASFADXXNN-SCRDCRAPSA-N
 Ligand Interaction
PYR
Query on PYR

Download CCD File 
B
PYRUVIC ACID
C3 H4 O3
LCTONWCANYUPML-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Observed: 0.188 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 165.51α = 90
b = 165.51β = 90
c = 113.71γ = 120
Software Package:
Software NamePurpose
PROFFTrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1991-01-15
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance