1xpy: Difference between revisions

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Structural Basis for Catalytic Racemization and Substrate Specificity of an N-Acylamino Acid Racemase Homologue from Deinococcus radiodurans

OverviewOverview

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 StructureAbout this Structure

1XPY is a Single protein structure of sequence from Deinococcus radiodurans with and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

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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-[[Image:1xpy.gif|left|200px]]<br /><applet load="1xpy" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1xpy, resolution 2.30&Aring;" />
 '''Structural Basis for Catalytic Racemization and Substrate Specificity of an N-Acylamino Acid Racemase Homologue from Deinococcus radiodurans'''<br />
 ==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.
+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==
-XPY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans] with MG and NLQ as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1XPY OCA].
+XPY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Deinococcus_radiodurans Deinococcus radiodurans] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=NLQ:'>NLQ</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XPY OCA].
 ==Reference==
@@ Line 13: / Line 13: @@
 [[Category: Deinococcus radiodurans]]
 [[Category: Single protein]]
-[[Category: Chen, C.Y.]]
+[[Category: Chen, C Y.]]
-[[Category: Chiu, W.C.]]
+[[Category: Chiu, W C.]]
-[[Category: Hsu, S.K.]]
+[[Category: Hsu, S K.]]
-[[Category: Hsu, W.H.]]
+[[Category: Hsu, W H.]]
-[[Category: Liu, J.S.]]
+[[Category: Liu, J S.]]
-[[Category: Wang, W.C.]]
+[[Category: Wang, W C.]]
-[[Category: Wu, C.L.]]
+[[Category: Wu, C L.]]
 [[Category: MG]]
 [[Category: NLQ]]
 [[Category: racemase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Sun Nov 25 02:40:56 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:57:22 2008''