2aio: Difference between revisions

Revision as of 17:27, 21 February 2008

Metallo beta lactamase L1 from Stenotrophomonas maltophilia complexed with hydrolyzed moxalactam

OverviewOverview

Metallo-beta-lactamases are zinc-dependent enzymes responsible for resistance to beta-lactam antibiotics in a variety of host bacteria, usually Gram-negative species that act as opportunist pathogens. They hydrolyze all classes of beta-lactam antibiotics, including carbapenems, and escape the action of available beta-lactamase inhibitors. Efforts to develop effective inhibitors have been hampered by the lack of structural information regarding how these enzymes recognize and turn over beta-lactam substrates. We report here the crystal structure of the Stenotrophomonas maltophilia L1 enzyme in complex with the hydrolysis product of the 7alpha-methoxyoxacephem, moxalactam. The on-enzyme complex is a 3'-exo-methylene species generated by elimination of the 1-methyltetrazolyl-5-thiolate anion from the 3'-methyl group. Moxalactam binding to L1 involves direct interaction of the two active site zinc ions with the beta-lactam amide and C4 carboxylate, groups that are common to all beta-lactam substrates. The 7beta-[(4-hydroxyphenyl)malonyl]-amino substituent makes limited hydrophobic and hydrogen bonding contacts with the active site groove. The mode of binding provides strong evidence that a water molecule situated between the two metal ions is the most likely nucleophile in the hydrolytic reaction. These data suggest a reaction mechanism for metallo-beta-lactamases in which both metal ions contribute to catalysis by activating the bridging water/hydroxide nucleophile, polarizing the substrate amide bond for attack and stabilizing anionic nitrogen intermediates. The structure illustrates how a binuclear zinc site confers upon metallo-beta-lactamases the ability both to recognize and efficiently hydrolyze a wide variety of beta-lactam substrates.

About this StructureAbout this Structure

2AIO is a Single protein structure of sequence from Stenotrophomonas maltophilia with , and as ligands. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.

ReferenceReference

Antibiotic recognition by binuclear metallo-beta-lactamases revealed by X-ray crystallography., Spencer J, Read J, Sessions RB, Howell S, Blackburn GM, Gamblin SJ, J Am Chem Soc. 2005 Oct 19;127(41):14439-44. PMID:16218639

Page seeded by OCA on Thu Feb 21 16:27:48 2008

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

OCA

@@ Line 1: / Line 1: @@
-[[Image:2aio.gif|left|200px]]<br /><applet load="2aio" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:2aio.gif|left|200px]]<br /><applet load="2aio" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="2aio, resolution 1.70&Aring;" />
 '''Metallo beta lactamase L1 from Stenotrophomonas maltophilia complexed with hydrolyzed moxalactam'''<br />
 ==Overview==
-Metallo-beta-lactamases are zinc-dependent enzymes responsible for, resistance to beta-lactam antibiotics in a variety of host bacteria, usually Gram-negative species that act as opportunist pathogens. They, hydrolyze all classes of beta-lactam antibiotics, including carbapenems, and escape the action of available beta-lactamase inhibitors. Efforts to, develop effective inhibitors have been hampered by the lack of structural, information regarding how these enzymes recognize and turn over, beta-lactam substrates. We report here the crystal structure of the, Stenotrophomonas maltophilia L1 enzyme in complex with the hydrolysis, product of the 7alpha-methoxyoxacephem, moxalactam. The on-enzyme complex, is a 3'-exo-methylene species generated by elimination of the, 1-methyltetrazolyl-5-thiolate anion from the 3'-methyl group. Moxalactam, binding to L1 involves direct interaction of the two active site zinc ions, with the beta-lactam amide and C4 carboxylate, groups that are common to, all beta-lactam substrates. The 7beta-[(4-hydroxyphenyl)malonyl]-amino, substituent makes limited hydrophobic and hydrogen bonding contacts with, the active site groove. The mode of binding provides strong evidence that, a water molecule situated between the two metal ions is the most likely, nucleophile in the hydrolytic reaction. These data suggest a reaction, mechanism for metallo-beta-lactamases in which both metal ions contribute, to catalysis by activating the bridging water/hydroxide nucleophile, polarizing the substrate amide bond for attack and stabilizing anionic, nitrogen intermediates. The structure illustrates how a binuclear zinc, site confers upon metallo-beta-lactamases the ability both to recognize, and efficiently hydrolyze a wide variety of beta-lactam substrates.
+Metallo-beta-lactamases are zinc-dependent enzymes responsible for resistance to beta-lactam antibiotics in a variety of host bacteria, usually Gram-negative species that act as opportunist pathogens. They hydrolyze all classes of beta-lactam antibiotics, including carbapenems, and escape the action of available beta-lactamase inhibitors. Efforts to develop effective inhibitors have been hampered by the lack of structural information regarding how these enzymes recognize and turn over beta-lactam substrates. We report here the crystal structure of the Stenotrophomonas maltophilia L1 enzyme in complex with the hydrolysis product of the 7alpha-methoxyoxacephem, moxalactam. The on-enzyme complex is a 3'-exo-methylene species generated by elimination of the 1-methyltetrazolyl-5-thiolate anion from the 3'-methyl group. Moxalactam binding to L1 involves direct interaction of the two active site zinc ions with the beta-lactam amide and C4 carboxylate, groups that are common to all beta-lactam substrates. The 7beta-[(4-hydroxyphenyl)malonyl]-amino substituent makes limited hydrophobic and hydrogen bonding contacts with the active site groove. The mode of binding provides strong evidence that a water molecule situated between the two metal ions is the most likely nucleophile in the hydrolytic reaction. These data suggest a reaction mechanism for metallo-beta-lactamases in which both metal ions contribute to catalysis by activating the bridging water/hydroxide nucleophile, polarizing the substrate amide bond for attack and stabilizing anionic nitrogen intermediates. The structure illustrates how a binuclear zinc site confers upon metallo-beta-lactamases the ability both to recognize and efficiently hydrolyze a wide variety of beta-lactam substrates.
 ==About this Structure==
-AIO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Stenotrophomonas_maltophilia Stenotrophomonas maltophilia] with ZN, SO4 and MX1 as [http://en.wikipedia.org/wiki/ligands ligands]. 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=2AIO OCA].
+AIO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Stenotrophomonas_maltophilia Stenotrophomonas maltophilia] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=MX1:'>MX1</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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=2AIO OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Single protein]]
 [[Category: Stenotrophomonas maltophilia]]
-[[Category: Blackburn, G.M.]]
+[[Category: Blackburn, G M.]]
-[[Category: Gamblin, S.J.]]
+[[Category: Gamblin, S J.]]
 [[Category: Howell, S.]]
 [[Category: Read, J.]]
-[[Category: Sessions, R.B.]]
+[[Category: Sessions, R B.]]
 [[Category: Spencer, J.]]
 [[Category: MX1]]
@@ Line 29: / Line 29: @@
 [[Category: zinc]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 08:08:54 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:27:48 2008''