1oqz: Difference between revisions
New page: left|200px<br /><applet load="1oqz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1oqz, resolution 2.50Å" /> '''Crystal Structures o... |
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[[Image:1oqz.gif|left|200px]]<br /><applet load="1oqz" size=" | [[Image:1oqz.gif|left|200px]]<br /><applet load="1oqz" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1oqz, resolution 2.50Å" /> | caption="1oqz, resolution 2.50Å" /> | ||
'''Crystal Structures of Glutaryl 7-Aminocephalosporanic Acid Acylase: Insight into Autoproteolytic Activation'''<br /> | '''Crystal Structures of Glutaryl 7-Aminocephalosporanic Acid Acylase: Insight into Autoproteolytic Activation'''<br /> | ||
==Overview== | ==Overview== | ||
Glutaryl 7-aminocephalosporanic acid acylase (GCA, EC 3.5.1.11) is a | Glutaryl 7-aminocephalosporanic acid acylase (GCA, EC 3.5.1.11) is a member of N-terminal nucleophile (Ntn) hydrolases. The native enzyme is an (alpha beta)(2) heterotetramer originated from an enzymatically inactive precursor of a single polypeptide. The activation of precursor GCA consists of primary and secondary autoproteolytic cleavages, generating a terminal residue with both a nucleophile and a base and releasing a nine amino acid spacer peptide. We have determined the crystal structures of the recombinant selenomethionyl native and S170A mutant precursor from Pseudomonas sp. strain GK16. Precursor activation is likely triggered by conformational constraints within the spacer peptide, probably inducing a peptide flip. Autoproteolytic site solvent molecules, which have been trapped in a hydrophobic environment by the spacer peptide, may play a role as a general base for nucleophilic attack. The activation results in building up a catalytic triad composed of Ser170/His192/Glu624. However, the triad is not linked to the usual hydroxyl but the free alpha-amino group of the N-terminal serine residue of the native GCA. Mutagenesis and structural data support the notion that the stabilization of a transient hydroxazolidine ring during autoproteolysis would be critical during the N --> O acyl shift. The autoproteolytic activation mechanism for GCA is described. | ||
==About this Structure== | ==About this Structure== | ||
1OQZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_sp._se83 Pseudomonas sp. se83]. Full crystallographic information is available from [http:// | 1OQZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_sp._se83 Pseudomonas sp. se83]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OQZ OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Dauter, Z.]] | [[Category: Dauter, Z.]] | ||
[[Category: Kim, J | [[Category: Kim, J K.]] | ||
[[Category: Kim, K | [[Category: Kim, K H.]] | ||
[[Category: Lee, Y | [[Category: Lee, Y S.]] | ||
[[Category: Park, S | [[Category: Park, S S.]] | ||
[[Category: Rhee, S.]] | [[Category: Rhee, S.]] | ||
[[Category: Yang, I | [[Category: Yang, I S.]] | ||
[[Category: ala mutant]] | [[Category: ala mutant]] | ||
[[Category: glutaryl 7-aminocephalosporanic acid]] | [[Category: glutaryl 7-aminocephalosporanic acid]] | ||
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[[Category: n-terminal nucleophile (ntn) hydrolases]] | [[Category: n-terminal nucleophile (ntn) hydrolases]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:20:37 2008'' | ||
Revision as of 12:20, 21 February 2008
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Crystal Structures of Glutaryl 7-Aminocephalosporanic Acid Acylase: Insight into Autoproteolytic Activation
Overview
Glutaryl 7-aminocephalosporanic acid acylase (GCA, EC 3.5.1.11) is a member of N-terminal nucleophile (Ntn) hydrolases. The native enzyme is an (alpha beta)(2) heterotetramer originated from an enzymatically inactive precursor of a single polypeptide. The activation of precursor GCA consists of primary and secondary autoproteolytic cleavages, generating a terminal residue with both a nucleophile and a base and releasing a nine amino acid spacer peptide. We have determined the crystal structures of the recombinant selenomethionyl native and S170A mutant precursor from Pseudomonas sp. strain GK16. Precursor activation is likely triggered by conformational constraints within the spacer peptide, probably inducing a peptide flip. Autoproteolytic site solvent molecules, which have been trapped in a hydrophobic environment by the spacer peptide, may play a role as a general base for nucleophilic attack. The activation results in building up a catalytic triad composed of Ser170/His192/Glu624. However, the triad is not linked to the usual hydroxyl but the free alpha-amino group of the N-terminal serine residue of the native GCA. Mutagenesis and structural data support the notion that the stabilization of a transient hydroxazolidine ring during autoproteolysis would be critical during the N --> O acyl shift. The autoproteolytic activation mechanism for GCA is described.
About this Structure
1OQZ is a Single protein structure of sequence from Pseudomonas sp. se83. Full crystallographic information is available from OCA.
Reference
Crystal structures of glutaryl 7-aminocephalosporanic acid acylase: insight into autoproteolytic activation., Kim JK, Yang IS, Rhee S, Dauter Z, Lee YS, Park SS, Kim KH, Biochemistry. 2003 Apr 15;42(14):4084-93. PMID:12680762
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