1bvt: Difference between revisions

Revision as of 12:59, 21 February 2008

METALLO-BETA-LACTAMASE FROM BACILLUS CEREUS 569/H/9

OverviewOverview

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.

About this StructureAbout this Structure

1BVT is a Single protein structure of sequence from Bacillus cereus with and as ligands. This structure supersedes the now removed PDB entry 1BME. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.

ReferenceReference

1.85 A resolution structure of the zinc (II) beta-lactamase from Bacillus cereus., Carfi A, Duee E, Galleni M, Frere JM, Dideberg O, Acta Crystallogr D Biol Crystallogr. 1998 May 1;54(Pt 3):313-23. PMID:9761898

Page seeded by OCA on Thu Feb 21 11:59:37 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
-[[Image:1bvt.gif|left|200px]]<br /><applet load="1bvt" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1bvt.gif|left|200px]]<br /><applet load="1bvt" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1bvt, resolution 1.85&Aring;" />
 '''METALLO-BETA-LACTAMASE FROM BACILLUS CEREUS 569/H/9'''<br />
 ==Overview==
-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.
+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.
 ==About this Structure==
-BVT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_cereus Bacillus cereus] with ZN and BCT as [http://en.wikipedia.org/wiki/ligands ligands]. This structure superseeds the now removed PDB entry 1BME. Active as [http://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1BVT OCA].
+BVT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_cereus Bacillus cereus] with <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=BCT:'>BCT</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1BME. Active as [http://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BVT OCA].
 ==Reference==
@@ Line 23: / Line 23: @@
 [[Category: zinc]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 11:57:36 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:59:37 2008''