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< | ==Bacillus cereus metallo-beta-lactamase (BcII) Arg (121) Cys mutant. Solved at pH4.5 using 20mM ZnSO4 in the buffer. 1mM DTT and 1mM TCEP- HCl were used as reducing agents. Cys221 is reduced.== | ||
<StructureSection load='2bg2' size='340' side='right'caption='[[2bg2]], [[Resolution|resolution]] 2.40Å' scene=''> | |||
You may | == Structural highlights == | ||
<table><tr><td colspan='2'>[[2bg2]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_cereus Bacillus cereus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BG2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BG2 FirstGlance]. <br> | |||
or | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.4Å</td></tr> | ||
-- | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2bg2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2bg2 OCA], [https://pdbe.org/2bg2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2bg2 RCSB], [https://www.ebi.ac.uk/pdbsum/2bg2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2bg2 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/BLA2_BACCE BLA2_BACCE] Can hydrolyze carbapenem compounds. | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/bg/2bg2_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2bg2 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The zinc-dependent metallo-beta-lactamases are a group of bacterial enzymes that pose a threat to the future efficacy of present-day antibiotics. Their mechanism is poorly understood, and there are no clinically useful inhibitors. While most members of the group contain two tightly bound zinc ions in their active sites, the Bacillus cereus enzyme has a much lower affinity for its second zinc (Zn2), thought to be due to the presence of Arg121 immediately beneath the floor of the active site (cf. Cys/Ser/His121 in the bizinc enzymes). Crystal structures of the Arg121Cys mutant of the B. cereus 569/H/9 enzyme were solved at pH 7.0, 5.0, and 4.5, each in the presence of either 20 microM or 20 mM Zn(2+) to generate the mono- and bizinc forms, respectively. Surprisingly, the structure of the active site was unaffected by the mutation; a network of ordered water molecules replaced the interactions made by the arginine side chain, and the occupancy of Zn2 appeared minimally changed. As the pH was lowered, Zn2 moved away from one of its ligands, Asp120, but was "tracked" by two others, Cys221 and His263. Furthermore, the hydroxide ion (and proposed nucleophile for beta-lactam hydrolysis) was bound to Zn1 at pH 5 and above but absent at pH 4.5. This provides experimental evidence for an earlier proposed mechanism in which protonation of Asp120 and the Zn1-bound hydroxide are the two events that lead to the loss of activity at low pH. | |||
Effect of pH on the active site of an Arg121Cys mutant of the metallo-beta-lactamase from Bacillus cereus: implications for the enzyme mechanism.,Davies AM, Rasia RM, Vila AJ, Sutton BJ, Fabiane SM Biochemistry. 2005 Mar 29;44(12):4841-9. PMID:15779910<ref>PMID:15779910</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 2bg2" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Beta-lactamase 3D structures|Beta-lactamase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
== | |||
[[Category: Bacillus cereus]] | [[Category: Bacillus cereus]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Davies AM]] | |||
[[Category: Davies | [[Category: Fabiane SM]] | ||
[[Category: Fabiane | [[Category: Rasia RM]] | ||
[[Category: Rasia | [[Category: Sutton BJ]] | ||
[[Category: Sutton | [[Category: Vila AJ]] | ||
[[Category: Vila | |||
Latest revision as of 16:34, 13 December 2023
Bacillus cereus metallo-beta-lactamase (BcII) Arg (121) Cys mutant. Solved at pH4.5 using 20mM ZnSO4 in the buffer. 1mM DTT and 1mM TCEP- HCl were used as reducing agents. Cys221 is reduced.Bacillus cereus metallo-beta-lactamase (BcII) Arg (121) Cys mutant. Solved at pH4.5 using 20mM ZnSO4 in the buffer. 1mM DTT and 1mM TCEP- HCl were used as reducing agents. Cys221 is reduced.
Structural highlights
FunctionBLA2_BACCE Can hydrolyze carbapenem compounds. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe zinc-dependent metallo-beta-lactamases are a group of bacterial enzymes that pose a threat to the future efficacy of present-day antibiotics. Their mechanism is poorly understood, and there are no clinically useful inhibitors. While most members of the group contain two tightly bound zinc ions in their active sites, the Bacillus cereus enzyme has a much lower affinity for its second zinc (Zn2), thought to be due to the presence of Arg121 immediately beneath the floor of the active site (cf. Cys/Ser/His121 in the bizinc enzymes). Crystal structures of the Arg121Cys mutant of the B. cereus 569/H/9 enzyme were solved at pH 7.0, 5.0, and 4.5, each in the presence of either 20 microM or 20 mM Zn(2+) to generate the mono- and bizinc forms, respectively. Surprisingly, the structure of the active site was unaffected by the mutation; a network of ordered water molecules replaced the interactions made by the arginine side chain, and the occupancy of Zn2 appeared minimally changed. As the pH was lowered, Zn2 moved away from one of its ligands, Asp120, but was "tracked" by two others, Cys221 and His263. Furthermore, the hydroxide ion (and proposed nucleophile for beta-lactam hydrolysis) was bound to Zn1 at pH 5 and above but absent at pH 4.5. This provides experimental evidence for an earlier proposed mechanism in which protonation of Asp120 and the Zn1-bound hydroxide are the two events that lead to the loss of activity at low pH. Effect of pH on the active site of an Arg121Cys mutant of the metallo-beta-lactamase from Bacillus cereus: implications for the enzyme mechanism.,Davies AM, Rasia RM, Vila AJ, Sutton BJ, Fabiane SM Biochemistry. 2005 Mar 29;44(12):4841-9. PMID:15779910[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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