1RVV

SYNTHASE/RIBOFLAVIN SYNTHASE COMPLEX OF BACILLUS SUBTILIS

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Work: 0.237 

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This is version 1.2 of the entry. See complete history. 

Literature

Studies on the lumazine synthase/riboflavin synthase complex of Bacillus subtilis: crystal structure analysis of reconstituted, icosahedral beta-subunit capsids with bound substrate analogue inhibitor at 2.4 A resolution.

Ritsert, K., Huber, R., Turk, D., Ladenstein, R., Schmidt-Base, K., Bacher, A.

(1995) J.Mol.Biol. 253: 151-167

  • DOI: 10.1006/jmbi.1995.0542

  • PubMed Abstract: 

    • The lumazine synthase/riboflavin synthase of Bacillus subtilis is a bifunctional enzyme complex catalysing the formation of riboflavin from 5-amino-6-(D-ribitylamino)-2,4(1H,3H)-pyrimidinedione and L-3,4-dihydroxy-2-butanone-4-phosphate via 6,7-dimet ...

    The lumazine synthase/riboflavin synthase of Bacillus subtilis is a bifunctional enzyme complex catalysing the formation of riboflavin from 5-amino-6-(D-ribitylamino)-2,4(1H,3H)-pyrimidinedione and L-3,4-dihydroxy-2-butanone-4-phosphate via 6,7-dimethyl-8-ribityllumazine. The complex is composed of 3 alpha (riboflavin synthase) subunits and 60 beta (lumazine synthase) subunits and has a relative mass of 1 MDa. The 60 beta subunits are arranged in an icosahedral capsid enclosing the alpha trimer in the central core. The protein was crystallised, and an X-ray structure of the icosahedral capsid was obtained at 3.3 A resolution with a crystallographic R-factor of 0.33. Hollow, icosahedral capsids consisting of 60 beta subunits can be obtained by inhibitor-driven renaturation of isolated beta subunits. They catalyse the formation of 6,7-dimethyl-8-ribityllumazine at the same rate as the native alpha 3 beta 60 complex and can be crystallised in two different hexagonal and one monoclinic form. Crystallographic intensity data of the monoclinic crystals to a resolution of 2.4 A were obtained using synchrotron radiation and an image plate detector system. The orientation of the icosahedral molecules in the monoclinic cell was deduced by real space vector search procedures from a 3.5 A Patterson map. Phases were calculated from the model of the alpha 3 beta 60 protein and were extended by cyclic averaging exploring the 30-fold redundancy of the electron density. The 2.4 A map allowed us to refine the existing atomic model of lumazine synthase. The refined model includes 154 amino acid residues, one inhibitor molecule, 58 water molecules and one phosphate ion. Applying non-crystallographic-symmetry restraints the crystallographic R-factor is 16.7% for 100,092 reflections between 10 and 2.4 A. The chain folding of the beta subunits is closely similar to the native alpha 3 beta 60 enzyme. The lumazine synthase bears resemblance to the sugar binding proteins. The significantly higher resolution compared to the alpha 3 beta 60 structure determination allows a detailed description of the substrate analogue binding site. The environment of the 5-nitro-6-(D-ribitylamino)-2,4(1H,3H)-pyrimidinedione inhibitor is particularly rigid, and the chain segments involved in forming the active site are highly conserved for lumazine synthases of different species. A residual density feature in the final map is interpreted as a bound phosphate which mimics the binding of the second substrate. We discuss the reaction mechanism on this structural basis.

    Organizational Affiliation: 

    Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
RIBOFLAVIN SYNTHASE
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, 1, 2, 3, 4
154Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: ribH
EC: 2.5.1.78
Find proteins for P11998 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P11998
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4
Download SDF File 
Download CCD File 
1, 2, 3, 4, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
INI
Query on INI
Download SDF File 
Download CCD File 
1, 2, 3, 4, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z
5-NITRO-6-RIBITYL-AMINO-2,4(1H,3H)-PYRIMIDINEDIONE
C9 H14 N4 O8
KSKGHNZSCSCHEQ-RPDRRWSUSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Work: 0.237 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 235.900α = 90.00
b = 192.600β = 134.90
c = 168.600γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORphasing
X-PLORrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-12-07
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance