Investigation into the membrane interaction of E.coli Pencillin binding protein 4
type: CreativeWork
description: The low molecular mass penicillin-binding proteins (PBPs) of E. coli play a regulatory role in the terminal stages of peptidoglycan biosynthesis. PBPs 4, 5 and 6 have been shown to possess DD-carboxypeptidase activity with PBP4 also having an endopeptidase activity. PBP5 and 6 are proposed to anchor to the periplasmic face of the inner membrane via C-terminal ahelices whereas the association of PBP4 with the membrane is more ambiguous and may involve a specific binding site and/or C-terminal amphiphilic a-helical interaction. PBP4 has also been tentatively proposed to function as part of an enzyme complex that serves to insert new peptidoglycan strands into the pre-existing layer surrounding the bacterial cell. The effect that P4, a C-terminal homologue of PBP4, had on an artificial bilayer has been investigated using 2H NMR. This has been compared with the interactions of P5, a PBP5 C-terminal homologue, and melittin, a well documented membrane interactive protein of similar molecular mass. In the NMR experiments it was found that splitting reduced with increasing P4 concentration (0 - 8.27 mg.g5, P<0.088. A similar, though less convincing, effect was observed with P5 (0 - 6.94 mg.gj, P<0.86, and melittin (0 - 3.06 mg.g 1 ), Pc0.39. This data implies that P4 interferes with the lamellar structure to a greater degree than either PS or melittin, possibly causing disruption, and would support a role for the C-terminus of PBP4 in membrane binding. In monolayer experiments, P4 produced an increase in surface pressure of between 1 and 7.5 mN m 1 , with monolayers formed with either dioleoylphosphatodylglycerol (DOPO), dioleoylphosphatidylethanolamine (DOPE), a mixed lipid system (75% DOPE, 20% DOPG, 5% cardiolipin) or E. coli lipid extract. Similar pressure increases were observed with the addition of NaC1 (1 and 10 gM) to the sub phase of DOPG and lipid extract monolayers. This data confirms that the C-terminus of the protein would be able to interact with the bilayer i…
abstract: The low molecular mass penicillin-binding proteins (PBPs) of E. coli play a regulatory role in the terminal stages of peptidoglycan biosynthesis. PBPs 4, 5 and 6 have been shown to possess DD-carboxypeptidase activity with PBP4 also having an endopeptidase activity. PBP5 and 6 are proposed to anchor to the periplasmic face of the inner membrane via C-terminal ahelices whereas the association of PBP4 with the membrane is more ambiguous and may involve a specific binding site and/or C-terminal amphiphilic a-helical interaction. PBP4 has also been tentatively proposed to function as part of an enzyme complex that serves to insert new peptidoglycan strands into the pre-existing layer surrounding the bacterial cell. The effect that P4, a C-terminal homologue of PBP4, had on an artificial bilayer has been investigated using 2H NMR. This has been compared with the interactions of P5, a PBP5 C-terminal homologue, and melittin, a well documented membrane interactive protein of similar molecular mass. In the NMR experiments it was found that splitting reduced with increasing P4 concentration (0 - 8.27 mg.g5, P<0.088. A similar, though less convincing, effect was observed with P5 (0 - 6.94 mg.gj, P<0.86, and melittin (0 - 3.06 mg.g 1 ), Pc0.39. This data implies that P4 interferes with the lamellar structure to a greater degree than either PS or melittin, possibly causing disruption, and would support a role for the C-terminus of PBP4 in membrane binding. In monolayer experiments, P4 produced an increase in surface pressure of between 1 and 7.5 mN m 1 , with monolayers formed with either dioleoylphosphatodylglycerol (DOPO), dioleoylphosphatidylethanolamine (DOPE), a mixed lipid system (75% DOPE, 20% DOPG, 5% cardiolipin) or E. coli lipid extract. Similar pressure increases were observed with the addition of NaC1 (1 and 10 gM) to the sub phase of DOPG and lipid extract monolayers. This data confirms that the C-terminus of the protein would be able to interact with the bilayer i…
author: Swan, Ruth
language: en
date published: 2005-01
date modified: 2026-07-24T01:36:16Z
provider: University of Central Lancashire
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Central Lancashire