1e3a
From Proteopedia
(New page: 200px<br /><applet load="1e3a" size="450" color="white" frame="true" align="right" spinBox="true" caption="1e3a, resolution 1.8Å" /> '''A SLOW PROCESSING PRE...) |
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| - | [[Image:1e3a.gif|left|200px]]<br /><applet load="1e3a" size=" | + | [[Image:1e3a.gif|left|200px]]<br /><applet load="1e3a" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1e3a, resolution 1.8Å" /> | caption="1e3a, resolution 1.8Å" /> | ||
'''A SLOW PROCESSING PRECURSOR PENICILLIN ACYLASE FROM ESCHERICHIA COLI'''<br /> | '''A SLOW PROCESSING PRECURSOR PENICILLIN ACYLASE FROM ESCHERICHIA COLI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Penicillin G acylase is a periplasmic protein, cytoplasmically expressed | + | Penicillin G acylase is a periplasmic protein, cytoplasmically expressed as a precursor polypeptide comprising a signal sequence, the A and B chains of the mature enzyme (209 and 557 residues respectively) joined by a spacer peptide of 54 amino acid residues. The wild-type AB heterodimer is produced by proteolytic removal of this spacer in the periplasm. The first step in processing is believed to be autocatalytic hydrolysis of the peptide bond between the C-terminal residue of the spacer and the active-site serine residue at the N terminus of the B chain. We have determined the crystal structure of a slowly processing precursor mutant (Thr263Gly) of penicillin G acylase from Escherichia coli, which reveals that the spacer peptide blocks the entrance to the active-site cleft consistent with an autocatalytic mechanism of maturation. In this mutant precursor there is, however, an unexpected cleavage at a site four residues from the active-site serine residue. Analyses of the stereochemistry of the 260-261 bond seen to be cleaved in this precursor structure and of the 263-264 peptide bond have suggested factors that may govern the autocatalytic mechanism. |
==About this Structure== | ==About this Structure== | ||
| - | 1E3A is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with EDO as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Penicillin_amidase Penicillin amidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.11 3.5.1.11] Full crystallographic information is available from [http:// | + | 1E3A is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Penicillin_amidase Penicillin amidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.11 3.5.1.11] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E3A OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Penicillin amidase]] | [[Category: Penicillin amidase]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Dodson, G | + | [[Category: Dodson, G G.]] |
[[Category: Hewitt, L.]] | [[Category: Hewitt, L.]] | ||
[[Category: Kasche, V.]] | [[Category: Kasche, V.]] | ||
| - | [[Category: Lewis, R | + | [[Category: Lewis, R J.]] |
[[Category: Lummer, K.]] | [[Category: Lummer, K.]] | ||
| - | [[Category: Murshudov, G | + | [[Category: Murshudov, G N.]] |
| - | [[Category: Verma, C | + | [[Category: Verma, C S.]] |
| - | [[Category: Wilson, K | + | [[Category: Wilson, K S.]] |
[[Category: EDO]] | [[Category: EDO]] | ||
[[Category: amidase]] | [[Category: amidase]] | ||
| Line 27: | Line 27: | ||
[[Category: ntn-hydrolase]] | [[Category: ntn-hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:23:20 2008'' |
Revision as of 10:23, 21 February 2008
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A SLOW PROCESSING PRECURSOR PENICILLIN ACYLASE FROM ESCHERICHIA COLI
Overview
Penicillin G acylase is a periplasmic protein, cytoplasmically expressed as a precursor polypeptide comprising a signal sequence, the A and B chains of the mature enzyme (209 and 557 residues respectively) joined by a spacer peptide of 54 amino acid residues. The wild-type AB heterodimer is produced by proteolytic removal of this spacer in the periplasm. The first step in processing is believed to be autocatalytic hydrolysis of the peptide bond between the C-terminal residue of the spacer and the active-site serine residue at the N terminus of the B chain. We have determined the crystal structure of a slowly processing precursor mutant (Thr263Gly) of penicillin G acylase from Escherichia coli, which reveals that the spacer peptide blocks the entrance to the active-site cleft consistent with an autocatalytic mechanism of maturation. In this mutant precursor there is, however, an unexpected cleavage at a site four residues from the active-site serine residue. Analyses of the stereochemistry of the 260-261 bond seen to be cleaved in this precursor structure and of the 263-264 peptide bond have suggested factors that may govern the autocatalytic mechanism.
About this Structure
1E3A is a Protein complex structure of sequences from Escherichia coli with as ligand. Active as Penicillin amidase, with EC number 3.5.1.11 Full crystallographic information is available from OCA.
Reference
Structure of a slow processing precursor penicillin acylase from Escherichia coli reveals the linker peptide blocking the active-site cleft., Hewitt L, Kasche V, Lummer K, Lewis RJ, Murshudov GN, Verma CS, Dodson GG, Wilson KS, J Mol Biol. 2000 Sep 29;302(4):887-98. PMID:10993730
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