 |
PDBsum entry 1cb7
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Glutamate mutase from clostridium cochlearium: the structure of a coenzyme b12-Dependent enzyme provides new mechanistic insights.
|
|
|
Authors
|
|
R.Reitzer,
K.Gruber,
G.Jogl,
U.G.Wagner,
H.Bothe,
W.Buckel,
C.Kratky.
|
|
|
Ref.
|
|
Structure, 1999,
7,
891-902.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
BACKGROUND: Glutamate mutase (Glm) equilibrates (S)-glutamate with
(2S,3S)-3-methylaspartate. Catalysis proceeds with the homolytic cleavage of the
organometallic bond of the cofactor to yield a 5'-desoxyadenosyl radical. This
radical then abstracts a hydrogen atom from the protein-bound substrate to
initiate the rearrangement reaction. Glm from Clostridium cochlearium is a
heterotetrameric molecule consisting of two sigma and two epsilon polypeptide
chains. RESULTS: We have determined the crystal structures of inactive
recombinant Glm reconstituted with either cyanocobalamin or methylcobalamin. The
molecule shows close similarity to the structure of methylmalonyl CoA mutase
(MCM), despite poor sequence similarity between its catalytic epsilon subunit
and the corresponding TIM-barrel domain of MCM. Each of the two independent B12
cofactor molecules is associated with a substrate-binding site, which was found
to be occupied by a (2S,3S)-tartrate ion. A 1:1 mixture of cofactors with cobalt
in oxidation states II and III was observed in both crystal structures of
inactive Glm. CONCLUSIONS: The long axial cobalt-nitrogen bond first observed in
the structure of MCM appears to result from a contribution of the species
without upper ligand. The tight binding of the tartrate ion conforms to the
requirements of tight control of the reactive intermediates and suggests how the
enzyme might use the substrate-binding energy to initiate cleavage of the
cobalt-carbon bond. The cofactor does not appear to have a participating role
during the radical rearrangement reaction.
|
|
|
|
|
|
Figure 5.
Figure 5. Ribbon representation of the  epsilon,
Greek [2]s[2](B[12])[2] tartrate[2] heterotetramer of Glm,
viewed down the noncrystallographic dyad. The two epsilon,
Greek subunits are coloured in red and green and the two s
subunits are in yellow and blue. The B[12] cofactors are in cyan
and the tartrate ions in magenta.
|
|
|
|
|
|
The above figure is
reprinted
by permission from Cell Press:
Structure
(1999,
7,
891-902)
copyright 1999.
|
|
|
Secondary reference #1
|
|
|
Title
|
|
Crystallization and preliminary X-Ray analysis of recombinant glutamate mutase and of the isolated component s from clostridium cochlearium.
|
|
|
Authors
|
|
R.Reitzer,
M.Krasser,
G.Jogl,
W.Buckel,
H.Bothe,
C.Kratky.
|
|
|
Ref.
|
|
Acta Crystallogr D Biol Crystallogr, 1998,
54,
1039-1042.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Figure 1.
Fig. 1. ata collection (EMBL beamline Xll, DESY, Hamburg) on
component S with cyanocobalamin. Exposure time 4 min, oscilla-
tion range 1.0 °.
|
|
Figure 3.
Fig. 3 Self-rotation function h~r component S with cyanocobalamin. A
section at x = 18ff is show. Data btween a resoltion of 10 and
4 A were used, integration radius 25 A. Contouring started at 15%
in 5% increments. The axis conventions are as follows: ~c is the
rotation axis whose orientation with respect to the (orthogonalized)
axes is defined by ~) (angle from z axis) and ~0 (angle in the x, y
plane).
|
|
|
|
|
|
The above figures are
reproduced from the cited reference
with permission from the IUCr
|
|
|
Secondary reference #2
|
|
|
Title
|
|
Characterization of the coenzyme-B12-Dependent glutamate mutase from clostridium cochlearium produced in escherichia coli.
|
|
|
Authors
|
|
O.Zelder,
B.Beatrix,
U.Leutbecher,
W.Buckel.
|
|
|
Ref.
|
|
Eur J Biochem, 1994,
226,
577-585.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
|
|
|
|
