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PDBsum entry 1bvt
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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1.85 a resolution structure of the zinc (ii) beta-Lactamase from bacillus cereus.
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Authors
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A.Carfi,
E.Duée,
M.Galleni,
J.M.Frère,
O.Dideberg.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1998,
54,
313-323.
[DOI no: ]
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PubMed id
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Abstract
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Class B beta-lactamases are wide spectrum enzymes which require bivalent metal
ions for activity. The structure of the class B zinc-ion-dependent
beta-lactamase from Bacillus cereus (BCII) has been refined at 1.85 A resolution
using data collected on cryocooled crystals (100 K). The enzyme from B. cereus
has a molecular mass of 24 946 Da and is folded into a beta-sandwich structure
with helices on the external faces. The active site is located in a groove
running between the two beta-sheets [Carfi et al. (1995). EMBO J. 14,
4914-4921]. The 100 K high-resolution BCII structure shows one fully and one
partially occupied zinc sites. The zinc ion in the fully occupied site (the
catalytic zinc) is coordinated by three histidines and one water molecule. The
second zinc ion is at 3.7 A from the first one and is coordinated by one
histidine, one cysteine, one aspartate and one unknown molecule (most likely a
carbonate ion). In the B. cereus zinc beta-lactamase the affinity for the second
metal-ion is low at the pH of crystallization (Kd = 25 mM, 293 K; [Baldwin et
al. (1978). Biochem. J. 175, 441-447] and the dissociation constant of the
second zinc ion was thus apparently decreased at the cryogenic temperature. In
addition, the structure of the apo enzyme was determined at 2.5 A resolution.
The removal of the zinc ion by chelating agents causes small changes in the
active-site environment.
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Figure 6.
Ball-and-stick representation of the active-sites environment of BCII and B. fragilis
zinc [\beta] -lactamases. The same orientation was used for the two views.
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Figure 7.
Ball-and-stick representation of the active sites environment of holo and apo BCII. The
same orientation was used for the two views.
[Figure 8]-[gr0751fig8thm.gif]
Figure 8
Stereoview of the C [\alpha] superposition of the apo (dotted lines) and holo (solid
line) BCII.
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(1998,
54,
313-323)
copyright 1998.
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Secondary reference #1
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Title
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The 3-D structure of a zinc metallo-Beta-Lactamase from bacillus cereus reveals a new type of protein fold.
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Authors
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A.Carfi,
S.Pares,
E.Duée,
M.Galleni,
C.Duez,
J.M.Frère,
O.Dideberg.
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Ref.
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Embo J, 1995,
14,
4914-4921.
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PubMed id
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