1alq
From Proteopedia
(New page: 200px<br /><applet load="1alq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1alq, resolution 1.80Å" /> '''CIRCULARLY PERMUTED ...) |
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| - | [[Image:1alq.jpg|left|200px]]<br /><applet load="1alq" size=" | + | [[Image:1alq.jpg|left|200px]]<br /><applet load="1alq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1alq, resolution 1.80Å" /> | caption="1alq, resolution 1.80Å" /> | ||
'''CIRCULARLY PERMUTED BETA-LACTAMASE FROM STAPHYLOCOCCUS AUREUS PC1'''<br /> | '''CIRCULARLY PERMUTED BETA-LACTAMASE FROM STAPHYLOCOCCUS AUREUS PC1'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The role that domain flexibility plays in the enzymatic activity of | + | The role that domain flexibility plays in the enzymatic activity of beta-lactamase from Staphylococcus aureus PC1 was investigated by producing two circularly permuted molecules. The C- and N-termini of the wild-type enzyme are adjacent to each other and remote from the active site, which is located between two domains. The polypeptide chain crosses over from one domain to the other twice. For the circularly permuted molecules, the termini were joined by an eight amino acid residue insertion, and new termini were introduced elsewhere. The first construct, termed cp254, was cleaved in a loop remote from the domain interface. The crystal structure of cp254 has been determined and refined at 1.8 A resolution, revealing essentially the same structure as that of the native protein. The activity profile with a representative sample of beta-lactam antibiotics is also very similar to that of wild-type beta-lactamase. The termini of the second circularly permuted mutant, cp228, occur within the second crossover region and therefore may enhance the flexibility of the molecule. Cp228 beta-lactamase shows a large decrease in enzymatic activity toward the sample of beta-lactam antibiotics, with catalytic rates that are 0.5-1% of those of the wild-type enzyme. One exception is the hydrolysis of the third generation cephalosporin, cefotaxime, which is hydrolyzed by the cp228 enzyme 10-fold faster than by wild-type beta-lactamase. Cp228 has not been crystallized. However, the circular dichroism spectra of the two circularly permuted proteins are very similar, indicating that, by analogy to cp254, cp228 adopts a global folded state. Thermal denaturation experiments reveal that cp254 is somewhat less stable than the wild-type enzyme, whereas cp228 is substantially less stable. Together, the data highlight the profound consequences that introducing flexibility at the domain interface has on both enzyme activity and protein stability. |
==About this Structure== | ==About this Structure== | ||
| - | 1ALQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with SO4 and CO3 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:// | + | 1ALQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=CO3:'>CO3</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=1ALQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:45:52 2008'' |
Revision as of 09:45, 21 February 2008
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CIRCULARLY PERMUTED BETA-LACTAMASE FROM STAPHYLOCOCCUS AUREUS PC1
Overview
The role that domain flexibility plays in the enzymatic activity of beta-lactamase from Staphylococcus aureus PC1 was investigated by producing two circularly permuted molecules. The C- and N-termini of the wild-type enzyme are adjacent to each other and remote from the active site, which is located between two domains. The polypeptide chain crosses over from one domain to the other twice. For the circularly permuted molecules, the termini were joined by an eight amino acid residue insertion, and new termini were introduced elsewhere. The first construct, termed cp254, was cleaved in a loop remote from the domain interface. The crystal structure of cp254 has been determined and refined at 1.8 A resolution, revealing essentially the same structure as that of the native protein. The activity profile with a representative sample of beta-lactam antibiotics is also very similar to that of wild-type beta-lactamase. The termini of the second circularly permuted mutant, cp228, occur within the second crossover region and therefore may enhance the flexibility of the molecule. Cp228 beta-lactamase shows a large decrease in enzymatic activity toward the sample of beta-lactam antibiotics, with catalytic rates that are 0.5-1% of those of the wild-type enzyme. One exception is the hydrolysis of the third generation cephalosporin, cefotaxime, which is hydrolyzed by the cp228 enzyme 10-fold faster than by wild-type beta-lactamase. Cp228 has not been crystallized. However, the circular dichroism spectra of the two circularly permuted proteins are very similar, indicating that, by analogy to cp254, cp228 adopts a global folded state. Thermal denaturation experiments reveal that cp254 is somewhat less stable than the wild-type enzyme, whereas cp228 is substantially less stable. Together, the data highlight the profound consequences that introducing flexibility at the domain interface has on both enzyme activity and protein stability.
About this Structure
1ALQ is a Single protein structure of sequence from Staphylococcus aureus with and as ligands. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
Reference
Circularly permuted beta-lactamase from Staphylococcus aureus PC1., Pieper U, Hayakawa K, Li Z, Herzberg O, Biochemistry. 1997 Jul 22;36(29):8767-74. PMID:9220963
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