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{{Sandbox_Reserved_ESBS}}<!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | {{Sandbox_Reserved_ESBS}}<!-- PLEASE ADD YOUR CONTENT BELOW HERE --> | ||
==Penicillin-binding protein 6== | ==Penicillin-binding protein 6== | ||
| - | The Penicillin-binding protein 6 (PBP6) is a DD-carboxypeptidase from ''Escherichia coli'' which plays an important role in the creation of the bacterial cell wall. Its structure was determined by Chen et al.<ref>PMID:19807181</ref> | + | The Penicillin-binding protein 6 (PBP6) is a DD-carboxypeptidase from ''Escherichia coli'' which plays an important role in the creation of the bacterial cell wall. Its structure was determined by Chen et al.<ref>PMID:19807181</ref>. |
<ref>DOI 10.1016/j.sbi.2010.09.014</ref> | <ref>DOI 10.1016/j.sbi.2010.09.014</ref> | ||
== Function == | == Function == | ||
| - | As a DD-carboxypeptidase, the function of PBP6 is to participate in the transpeptidation which occurs during the biosynthesis of peptidoglycan. More specifically, it cleaves the peptide bond between the two terminal D-alanines of muramyl peptides. This then allows transpeptidases to create peptidoglycan cross-links which stabilise the cell wall. Ampicillin <ref>DOI 10.1016/j.mib.2010.09.008</ref> | + | As a DD-carboxypeptidase, the function of PBP6 is to participate in the transpeptidation which occurs during the biosynthesis of peptidoglycan. More specifically, it cleaves the peptide bond between the two terminal D-alanines of muramyl peptides. This then allows transpeptidases to create peptidoglycan cross-links which stabilise the cell wall. |
| + | The cleavage reaction takes place in two step. | ||
| + | Firstly, the PBP6 binds to carbonyl group in the peptide bond between the two terminal D-alanines of the N-acetylmuramic acid. This forms a high-energy tetrahedric intermediate called the acylenzyme. [[3ita]] shows the acylenzyme complex of PBP6 with ampicillin. | ||
| + | The acylenzyme allows the medium to reach the carbonyle group. As a result, a water molecule can attack the group, causing the cleavage of the tetrahedral structure. | ||
| + | |||
| + | Ampicillin <ref>DOI 10.1016/j.mib.2010.09.008</ref> | ||
[[http://www.uniprot.org/uniprot/DACC_ECOLI DACC_ECOLI]] Removes C-terminal D-alanyl residues from sugar-peptide cell wall precursors. | [[http://www.uniprot.org/uniprot/DACC_ECOLI DACC_ECOLI]] Removes C-terminal D-alanyl residues from sugar-peptide cell wall precursors. | ||
== Structure== | == Structure== | ||
<StructureSection load='3ita' size='340' side='right' caption='[[3ita]], [[Resolution|resolution]] 1.80Å' scene=''> | <StructureSection load='3ita' size='340' side='right' caption='[[3ita]], [[Resolution|resolution]] 1.80Å' scene=''> | ||
| - | + | The PBP6 is composed of 4 monomers which are almost identical to each other. The differences are found in some loops and in the amino acids of the active site. | |
| - | + | ||
===Structure of the active site=== | ===Structure of the active site=== | ||
Revision as of 12:37, 11 January 2019
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Penicillin-binding protein 6
The Penicillin-binding protein 6 (PBP6) is a DD-carboxypeptidase from Escherichia coli which plays an important role in the creation of the bacterial cell wall. Its structure was determined by Chen et al.[1]. [2]
Function
As a DD-carboxypeptidase, the function of PBP6 is to participate in the transpeptidation which occurs during the biosynthesis of peptidoglycan. More specifically, it cleaves the peptide bond between the two terminal D-alanines of muramyl peptides. This then allows transpeptidases to create peptidoglycan cross-links which stabilise the cell wall. The cleavage reaction takes place in two step. Firstly, the PBP6 binds to carbonyl group in the peptide bond between the two terminal D-alanines of the N-acetylmuramic acid. This forms a high-energy tetrahedric intermediate called the acylenzyme. 3ita shows the acylenzyme complex of PBP6 with ampicillin. The acylenzyme allows the medium to reach the carbonyle group. As a result, a water molecule can attack the group, causing the cleavage of the tetrahedral structure.
Ampicillin [3] [DACC_ECOLI] Removes C-terminal D-alanyl residues from sugar-peptide cell wall precursors.
Structure
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