1r0m
From Proteopedia
(New page: 200px<br /><applet load="1r0m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r0m, resolution 1.3Å" /> '''Structure of Deinococ...) |
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| - | [[Image:1r0m.gif|left|200px]]<br /><applet load="1r0m" size=" | + | [[Image:1r0m.gif|left|200px]]<br /><applet load="1r0m" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1r0m, resolution 1.3Å" /> | caption="1r0m, resolution 1.3Å" /> | ||
'''Structure of Deinococcus radiodurans N-acylamino acid racemase at 1.3 : insights into a flexible binding pocket and evolution of enzymatic activity'''<br /> | '''Structure of Deinococcus radiodurans N-acylamino acid racemase at 1.3 : insights into a flexible binding pocket and evolution of enzymatic activity'''<br /> | ||
==Overview== | ==Overview== | ||
| - | N-acylamino acid racemase (NAAAR) catalyzes the racemization of | + | N-acylamino acid racemase (NAAAR) catalyzes the racemization of N-acylamino acids and can be used in concert with an aminoacylase to produce enantiopure alpha-amino acids, a process that has potential industrial applications. Here we have cloned and characterized an NAAAR homologue from a radiation-resistant ancient bacterium, Deinococcus radiodurans. The expressed NAAAR racemized various substrates at an optimal temperature of 60 degrees C and had Km values of 24.8 mM and 12.3 mM for N-acetyl-D-methionine and N-acetyl-L-methionine, respectively. The crystal structure of NAAAR was solved to 1.3 A resolution using multiwavelength anomalous dispersion (MAD) methods. The structure consists of a homooctamer in which each subunit has an architecture characteristic of enolases with a capping domain and a (beta/alpha)7 beta barrel domain. The NAAAR.Mg2+ and NAAAR.N-acetyl-L-glutamine.Mg2+ structures were also determined, allowing us to define the Lys170-Asp195-Glu220-Asp245-Lys269 framework for catalyzing 1,1-proton exchange of N-acylamino acids. Four subsites enclosing the substrate are identified: catalytic site, metal-binding site, side-chain-binding region, and a flexible lid region. The high conservation of catalytic and metal-binding sites in different enolases reflects the essentiality of a common catalytic platform, allowing these enzymes to robustly abstract alpha-protons of various carboxylate substrates efficiently. The other subsites involved in substrate recognition are less conserved, suggesting that divergent evolution has led to functionally distinct enzymes. |
==About this Structure== | ==About this Structure== | ||
| - | 1R0M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans]. Full crystallographic information is available from [http:// | + | 1R0M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R0M OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Deinococcus radiodurans]] | [[Category: Deinococcus radiodurans]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Chen, C | + | [[Category: Chen, C Y.]] |
| - | [[Category: Chiu, W | + | [[Category: Chiu, W C.]] |
| - | [[Category: Hsu, S | + | [[Category: Hsu, S K.]] |
| - | [[Category: Hsu, W | + | [[Category: Hsu, W H.]] |
| - | [[Category: Liu, J | + | [[Category: Liu, J S.]] |
| - | [[Category: Wang, W | + | [[Category: Wang, W C.]] |
| - | [[Category: Wu, C | + | [[Category: Wu, C L.]] |
[[Category: racemase]] | [[Category: racemase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:45:43 2008'' |
Revision as of 12:45, 21 February 2008
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Structure of Deinococcus radiodurans N-acylamino acid racemase at 1.3 : insights into a flexible binding pocket and evolution of enzymatic activity
Overview
N-acylamino acid racemase (NAAAR) catalyzes the racemization of N-acylamino acids and can be used in concert with an aminoacylase to produce enantiopure alpha-amino acids, a process that has potential industrial applications. Here we have cloned and characterized an NAAAR homologue from a radiation-resistant ancient bacterium, Deinococcus radiodurans. The expressed NAAAR racemized various substrates at an optimal temperature of 60 degrees C and had Km values of 24.8 mM and 12.3 mM for N-acetyl-D-methionine and N-acetyl-L-methionine, respectively. The crystal structure of NAAAR was solved to 1.3 A resolution using multiwavelength anomalous dispersion (MAD) methods. The structure consists of a homooctamer in which each subunit has an architecture characteristic of enolases with a capping domain and a (beta/alpha)7 beta barrel domain. The NAAAR.Mg2+ and NAAAR.N-acetyl-L-glutamine.Mg2+ structures were also determined, allowing us to define the Lys170-Asp195-Glu220-Asp245-Lys269 framework for catalyzing 1,1-proton exchange of N-acylamino acids. Four subsites enclosing the substrate are identified: catalytic site, metal-binding site, side-chain-binding region, and a flexible lid region. The high conservation of catalytic and metal-binding sites in different enolases reflects the essentiality of a common catalytic platform, allowing these enzymes to robustly abstract alpha-protons of various carboxylate substrates efficiently. The other subsites involved in substrate recognition are less conserved, suggesting that divergent evolution has led to functionally distinct enzymes.
About this Structure
1R0M is a Single protein structure of sequence from Deinococcus radiodurans. Full crystallographic information is available from OCA.
Reference
Structural basis for catalytic racemization and substrate specificity of an N-acylamino acid racemase homologue from Deinococcus radiodurans., Wang WC, Chiu WC, Hsu SK, Wu CL, Chen CY, Liu JS, Hsu WH, J Mol Biol. 2004 Sep 3;342(1):155-69. PMID:15313614
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