1k55
From Proteopedia
(New page: 200px<br /><applet load="1k55" size="450" color="white" frame="true" align="right" spinBox="true" caption="1k55, resolution 1.39Å" /> '''OXA 10 class D beta-...) |
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| - | [[Image:1k55.gif|left|200px]]<br /><applet load="1k55" size=" | + | [[Image:1k55.gif|left|200px]]<br /><applet load="1k55" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1k55, resolution 1.39Å" /> | caption="1k55, resolution 1.39Å" /> | ||
'''OXA 10 class D beta-lactamase at pH 7.5'''<br /> | '''OXA 10 class D beta-lactamase at pH 7.5'''<br /> | ||
==Overview== | ==Overview== | ||
| - | beta-Lactamases are the resistance enzymes for beta-lactam antibiotics, of | + | beta-Lactamases are the resistance enzymes for beta-lactam antibiotics, of which four classes are known. beta-lactamases hydrolyze the beta-lactam moieties of these antibiotics, rendering them inactive. It is shown herein that the class D OXA-10 beta-lactamase depends critically on an unusual carbamylated lysine as the basic residue for both the enzyme acylation and deacylation steps of catalysis. The formation of carbamylated lysine is reversible. Evidence is presented that this enzyme is dimeric and carbamylated in living bacteria. High-resolution x-ray structures for the native enzyme were determined at pH values of 6.0, 6.5, 7.5, and 8.5. Two dimers are present per asymmetric unit. One monomer in each dimer was carbamylated at pH 6.0, whereas all four monomers were fully carbamylated at pH 8.5. At the intermediate pH values, one monomer of each dimer was carbamylated, and the other showed a mixture of carbamylated and non-carbamylated lysines. It would appear that, as the pH increased for the sample, additional lysines were "titrated" by carbamylation. A handful of carbamylated lysines are known from protein crystallographic data, all of which have been attributed roles in structural stabilization (mostly as metal ligands) of the proteins. This paper reports a previously unrecognized role for a noncoordinated carbamylate lysine as a basic residue involved in mechanistic reactions of an enzyme, which indicates another means for expansion of the catalytic capabilities of the amino acids in nature beyond the 20 common amino acids in development of biological catalysts. |
==About this Structure== | ==About this Structure== | ||
| - | 1K55 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with SO4 and EDO 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:// | + | 1K55 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=EDO:'>EDO</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=1K55 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Maveyraud, L.]] | [[Category: Maveyraud, L.]] | ||
[[Category: Mobashery, S.]] | [[Category: Mobashery, S.]] | ||
| - | [[Category: Samama, J | + | [[Category: Samama, J P.]] |
[[Category: Vakulenko, S.]] | [[Category: Vakulenko, S.]] | ||
[[Category: EDO]] | [[Category: EDO]] | ||
| Line 25: | Line 25: | ||
[[Category: carbamylation]] | [[Category: carbamylation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:30:15 2008'' |
Revision as of 11:30, 21 February 2008
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OXA 10 class D beta-lactamase at pH 7.5
Overview
beta-Lactamases are the resistance enzymes for beta-lactam antibiotics, of which four classes are known. beta-lactamases hydrolyze the beta-lactam moieties of these antibiotics, rendering them inactive. It is shown herein that the class D OXA-10 beta-lactamase depends critically on an unusual carbamylated lysine as the basic residue for both the enzyme acylation and deacylation steps of catalysis. The formation of carbamylated lysine is reversible. Evidence is presented that this enzyme is dimeric and carbamylated in living bacteria. High-resolution x-ray structures for the native enzyme were determined at pH values of 6.0, 6.5, 7.5, and 8.5. Two dimers are present per asymmetric unit. One monomer in each dimer was carbamylated at pH 6.0, whereas all four monomers were fully carbamylated at pH 8.5. At the intermediate pH values, one monomer of each dimer was carbamylated, and the other showed a mixture of carbamylated and non-carbamylated lysines. It would appear that, as the pH increased for the sample, additional lysines were "titrated" by carbamylation. A handful of carbamylated lysines are known from protein crystallographic data, all of which have been attributed roles in structural stabilization (mostly as metal ligands) of the proteins. This paper reports a previously unrecognized role for a noncoordinated carbamylate lysine as a basic residue involved in mechanistic reactions of an enzyme, which indicates another means for expansion of the catalytic capabilities of the amino acids in nature beyond the 20 common amino acids in development of biological catalysts.
About this Structure
1K55 is a Single protein structure of sequence from Pseudomonas aeruginosa with and as ligands. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
Reference
Critical involvement of a carbamylated lysine in catalytic function of class D beta-lactamases., Golemi D, Maveyraud L, Vakulenko S, Samama JP, Mobashery S, Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14280-5. Epub 2001 Nov 27. PMID:11724923
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