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1.
Abdellah Benachour Rabia Ladjouzi André Le Jeune Laurent Hébert Simon Thorpe Pascal Courtin Marie-Pierre Chapot-Chartier Tomasz K. Prajsnar Simon J. Foster Stéphane Mesnage 《Journal of bacteriology》2012,194(22):6066-6073
Lysozyme is a key component of the innate immune response in humans that provides a first line of defense against microbes. The bactericidal effect of lysozyme relies both on the cell wall lytic activity of this enzyme and on a cationic antimicrobial peptide activity that leads to membrane permeabilization. Among Gram-positive bacteria, the opportunistic pathogen Enterococcus faecalis has been shown to be extremely resistant to lysozyme. This unusual resistance is explained partly by peptidoglycan O-acetylation, which inhibits the enzymatic activity of lysozyme, and partly by d-alanylation of teichoic acids, which is likely to inhibit binding of lysozyme to the bacterial cell wall. Surprisingly, combined mutations abolishing both peptidoglycan O-acetylation and teichoic acid alanylation are not sufficient to confer lysozyme susceptibility. In this work, we identify another mechanism involved in E. faecalis lysozyme resistance. We show that exposure to lysozyme triggers the expression of EF1843, a protein that is not detected under normal growth conditions. Analysis of peptidoglycan structure from strains with EF1843 loss- and gain-of-function mutations, together with in vitro assays using recombinant protein, showed that EF1843 is a peptidoglycan N-acetylglucosamine deacetylase. EF1843-mediated peptidoglycan deacetylation was shown to contribute to lysozyme resistance by inhibiting both lysozyme enzymatic activity and, to a lesser extent, lysozyme cationic antimicrobial activity. Finally, EF1843 mutation was shown to reduce the ability of E. faecalis to cause lethality in the Galleria mellonella infection model. Taken together, our results reveal that peptidoglycan deacetylation is a component of the arsenal that enables E. faecalis to thrive inside mammalian hosts, as both a commensal and a pathogen. 相似文献
2.
Stimulation of PgdA‐dependent peptidoglycan N‐deacetylation by GpsB‐PBP A1 in Listeria monocytogenes
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Jeanine Rismondo Sabrina Wamp Christine Aldridge Waldemar Vollmer Sven Halbedel 《Molecular microbiology》2018,107(4):472-487
Listeria monocytogenes and other pathogenic bacteria modify their peptidoglycan to protect it against enzymatic attack through the host innate immune system, such as the cell wall hydrolase lysozyme. During our studies on GpsB, a late cell division protein that controls activity of the bi‐functional penicillin binding protein PBP A1, we discovered that GpsB influences lysozyme resistance of L. monocytogenes as mutant strains lacking gpsB showed an increased lysozyme resistance. Deletion of pbpA1 corrected this effect, demonstrating that PBP A1 is also involved in this. Susceptibility to lysozyme mainly depends on two peptidoglycan modifying enzymes: The peptidoglycan N‐deacetylase PgdA and the peptidoglycan O‐acetyltransferase OatA. Genetic and biochemical experiments consistently demonstrated that the increased lysozyme resistance of the ΔgpsB mutant was PgdA‐dependent and OatA‐independent. Protein‐protein interaction studies supported the idea that GpsB, PBP A1 and PgdA form a complex in L. monocytogenes and identified the regions in PBP A1 and PgdA required for complex formation. These results establish a physiological connection between GpsB, PBP A1 and the peptidoglycan modifying enzyme PgdA. To our knowledge, this is the first reported link between a GpsB‐like cell division protein and factors important for escape from the host immune system. 相似文献
3.
Jian Feng Li Jie Zhang Zhen Zhang Chun Tao Kang Shuang Quan Zhang 《Current microbiology》2011,62(1):296-300
Antibacterial peptide CM4 (ABP-CM4) is a small cationic peptide with broad-spectrum activities against bacteria, fungi, and
tumor cells, which may possibly be used as an antimicrobial agent. To improve the expression level of CM4 in Escherichia coli, two tandem repeats of CM4 genes were cloned into the vector pSUMO to construct an expression vector pSUMO–2CM4. The fusion
protein SUMO–2CM4, purified by Ni2+-chelating chromatography, was cleaved by hydroxylamine hydrochloride to release recombinant CM4. After the cleaved sample
was re-applied to a Ni-IDA column, finally, about 48 mg recombinant CM4 was obtained from 1 L bacterial culture with no less
than 96% purity, which was the highest yield of CM4 reported so far. 相似文献
4.
Yangshin Park Jeong‐A. Lim Minsuk Kong Sangryeol Ryu Sangkee Rhee 《Molecular microbiology》2014,92(2):316-325
Bacteriophage SPN1S infects the pathogenic Gram‐negative bacterium Salmonella typhimurium and expresses endolysin for the release of phage progeny by degrading peptidoglycan of the host cell walls. Bacteriophage SPN1S endolysin exhibits high glycosidase activity against peptidoglycans, resulting in antimicrobial activity against a broad range of outer membrane‐permeabilized Gram‐negative bacteria. Here, we report a crystal structure of SPN1S endolysin, indicating that unlike most endolysins from Gram‐negative bacteria background, the α‐helical protein consists of two modular domains, a large and a small domain, with a concave groove between them. Comparison with other structurally homologous glycoside hydrolases indicated a possible peptidoglycan binding site in the groove, and the presence of a catalytic dyad in the vicinity of the groove, one residue in a large domain and the other in a junction between the two domains. The catalytic dyad was further validated by antimicrobial activity assay against outer membrane‐permeabilized Escherichia coli. The three‐helix bundle in the small domain containing a novel class of sequence motif exhibited binding affinity against outer membrane‐permeabilized E. coli and was therefore proposed as the peptidoglycan‐binding domain. These structural and functional features suggest that endolysin from a Gram‐negative bacterial background has peptidoglycan‐binding activity and performs glycoside hydrolase activity through the catalytic dyad. 相似文献
5.
Lysozyme from egg white was modified by covalent attachment of an oleyl group to the free amino groups of lysozyme. The aim of the chemical modification was to develop an effective antimicrobial lysozyme derivative against both gram-negative and gram-positive bacteria. Lysozyme with various degrees of modification was obtained by changing oleoyl chloride/lysozyme mass ratio. Lysozyme derivatives evidently exhibited an antimicrobial effect against Escherichia coli (ATCC 29998). The modification slightly changed the antimicrobial effect of lysozyme derivative against Staphylococcus aureus (ATCC 121002). Since there was a positive correlation between the modification degree and the antimicrobial effect against E. coli, it was concluded that the change in antimicrobial behavior was due to an increase in hydrophobicity of the enzyme molecule enabling it to penetrate through the bacterial membrane of E. coli. It was also shown that oleoyl chloride with an MIC value of 10 mg/mL was effective against both E. coli and S. aureus. 相似文献
6.
Rohanah Hussain Christopher L. Joannou Giuliano Siligardi 《International journal of peptide research and therapeutics》2006,12(3):269-273
Microbes are increasingly developing defensive mechanisms against known drugs via mutations. There are signs of emergence of superbugs immune to most known antibiotics available. The need for a new class of drugs to counteract this problem is of paramount importance for continued general well being of mankind. A new class of drugs, antimicrobial peptides, has not been fully exploited primarily due to high cytotoxicity, poor lipophilicity preventing systemic distribution and stability. We have synthesised 9-amino acid residue cationic peptides RH01 and RH02 lipidated with myristoyl and octyl groups respectively. These peptides exhibited potent antimicrobial activity and low cytotoxicity. The lipopeptide RH01 has antimicrobial activity against a broad range of microorganisms including bacteria, yeast and filamentous fungi with greatest activity toward Gram-positive bacteria, including S. aureus MRSA stain, MIC’s ranging between 2–8 μM. The MIC for Gram-negative bacteria was higher ranging from between 30–250 μM. RH01 also had antimicrobial activity towards fungi showing good activity against the pathogenic yeast Candida albicans but was less active towards the filamentous fungi Aspergillus niger. The antimicrobial activity of RH01 as a measure of Ki(50) for E. coli and S. aureus was 35–60 μM and 3–7 μM, respectively. In-house data showed the compound is bactericidal even at higher bacteria concentration. The octylated lipopeptide RH02 has similar activities towards S. aureus (3.3 μM) and E coli (53.3 μM) as the myristolated RH01. There was no haemolytic activity of the lipopeptide RH01 towards human blood. Acute intravenous toxicity study in mice showed that both RH01 and RH02 induced no macroscopic abnormalities at their highest non-lethal dose of 75 mg/kg and 150 mg/kg bodyweight, respectively.Australian Peptide Conference Issue. 相似文献
7.
Lai MJ Lin NT Hu A Soo PC Chen LK Chen LH Chang KC 《Applied microbiology and biotechnology》2011,90(2):529-539
To investigate the nature and origin of the antibacterial activity of the lytic phage ϕAB2 toward Acinetobacter baumannii, we successfully isolated and characterized a novel phage lysozyme (endolysin) from ϕAB2 and named it LysAB2. To analyze
antibacterial activity of LysAB2, the complete LysAB2 and two deletion derivatives were constructed, purified and characterized.
Zymographic assays showed that only the intact LysAB2 could lyse the peptidoglycan of A. baumannii and the Staphylococcus aureus cell wall. Antibacterial analysis also showed that only the intact LysAB2 retained the complete bactericidal activity. When
applied exogenously, LysAB2 exhibited a broad bacteriolytic activity against a number of Gram-negative and Gram-positive bacteria.
Thermostability assays indicated that LysAB2 was stable at 20∼40°C. Its optimal pH was 6.0, and it was active from pH 4 to
8. Scanning electron microscopy revealed that exposure to 500 μg ml−1 LysAB2 for up to 60 min caused a remarkable modification of the cell shape of the bacteria. Treating bacteria with LysAB2
clearly enhanced permeation of the bacterial cytoplasmic membrane. These results indicate that LysAB2 is an effective lysozyme
against bacteria, and they suggest that it is a good candidate for a therapeutic/disinfectant agent to control nosocomial
infections caused by multiple drug-resistant bacteria. 相似文献
8.
The NB-C1 gene, acquired from the result of data mining of the lactic acid bacteria genome, is a novel potential class IIa bacteriocin
gene with the characteristic YGNGVxC cluster. To produce soluble NB-C1 efficiently and overcome issues of protein toxicity,
we adopted a GFP fusion strategy using an Escherichia coli cell-free protein expression system. We constructed the expression vector pIVEX2.4d-GFP-NB-C1, which was expressed in both
the batch mode and the continuous exchange cell-free (CECF) systems. The amount of soluble fusion protein achieved from the
CECF system (2.2 mg/ml) was approximately three times higher than that in the batch mode (0.73 mg/ml). The soluble fusion
protein was purified via one-step Ni–NTA affinity chromatography, with a concentration of 0.26 mg/ml and a purity of 95%.
The purified NB-C1 showed strong antimicrobial activity against the indicator bacteria Listeria monocytogenes. 相似文献
9.
The investigation of the recombinant bovine lactoferrin-derived antimicrobial protein (rBLfA) demonstrates that the inter-lobe
region of bovine lactoferrin contributes to iron binding stability and antimicrobial activity against Staphylococcus aureus. rBLfA containing N-lobe (amino acid residues 1–333) and inter-lobe region (residues 334–344) was expressed in Pichia pastoris at shaking flask and fermentor level. The recombinant intact bovine lactoferrin (rBLf) and N-lobe (rBLfN) were expressed
in the same system as control. The physical–chemical parameters of rBLfA, rBLfN and rBLf including amino acid residues, molecular
weight, isoelectric point, net positive charge and instability index were computed and compared. The simulated tertiary structure
and the calculated surface net charge showed that rBLfA maintained original structure and exhibited a higher cationic feature
than rBLf and rBLfN. The three proteins showed different iron binding stability and antimicrobial activity. rBLfA released
iron in the pH range of 7.0–3.5, whereas rBLfN lost its iron over the pH range of 7.0–4.0 and iron release from rBLf occurred
in the pH range of 5.5–3.0. However, the minimum inhibition concentration of rBLfA against S. aureus ATCC25923 was 6.5 μmol/L, compared with 12.5 and 25 μmol/L that of rBLfN and rBLf, respectively. These results revealed that
S. aureus was more sensitive to rBLfA than rBLfN and rBLf. It appeared that the strong cationic character of inter-lobe region related
positively to the higher anti-S. aureus activity. 相似文献
10.
Production of Bioactive Human β-defensin-3 in Escherichia coli by Soluble Fusion Expression 总被引:2,自引:0,他引:2
A codon optimized mature human β-defensin-3 gene (smHBD3) was synthesized and fused with TrxA to construct pET32-smHBD3 vector, which was transformed into
E. coli BL21(DE3) and cultured in MBL medium. The volumetric productivity of fusion protein reached 0.99 g fusion protein l−1, i.e. 0.21 g mature HBD3 l−1. Ninety-six percentage of the fusion protein was in a soluble form and constituted about 45% of the total soluble protein.
After cell disruption, the soluble fusion protein was separated by affinity chromatography and cleaved by enterokinase, and
then the mature HBD3 was purified by cationic ion exchange chromatography. The overall recovery ratio of HBD3 was 43%. The
purified mature HBD3 demonstrated antimicrobial activity against E. coli.
Revisions requested 13 December 2005; Revisions received 24 January 2006 相似文献
11.
Expression of the cationic antimicrobial peptide lactoferricin fused with the anionic peptide in Escherichia coli 总被引:7,自引:0,他引:7
Kim HK Chun DS Kim JS Yun CH Lee JH Hong SK Kang DK 《Applied microbiology and biotechnology》2006,72(2):330-338
Direct expression of lactoferricin, an antimicrobial peptide, is lethal to Escherichia coli. For the efficient production of lactoferricin in E. coli, we developed an expression system in which the gene for the lysine- and arginine-rich cationic lactoferricin was fused to an anionic peptide gene to neutralize the basic property of lactoferricin, and successfully overexpressed the concatemeric fusion gene in E. coli. The lactoferricin gene was linked to a modified magainin intervening sequence gene by a recombinational polymerase chain reaction, thus producing an acidic peptide–lactoferricin fusion gene. The monomeric acidic peptide–lactoferricin fusion gene was multimerized and expressed in E. coli BL21(DE3) upon induction with isopropyl-β-d-thiogalactopyranoside. The expression levels of the fusion peptide reached the maximum at the tetramer, while further increases in the copy number of the fusion gene substantially reduced the peptide expression level. The fusion peptides were isolated and cleaved to generate the separate lactoferricin and acidic peptide. About 60 mg of pure recombinant lactoferricin was obtained from 1 L of E. coli culture. The purified recombinant lactoferricin was found to have a molecular weight similar to that of chemically synthesized lactoferricin. The recombinant lactoferricin showed antimicrobial activity and disrupted bacterial membrane permeability, as the native lactoferricin peptide does. 相似文献
12.
Yu-Chuan Juang Sunil S. Adav Duu-Jong Lee Juin-Yih Lai 《Applied microbiology and biotechnology》2009,85(2):383-388
Antibacterial peptide CM4 (ABP-CM4) is a small cationic peptide with broad-spectrum activities against bacteria, fungi, and
tumor cells, which may possibly be used as an antimicrobial agent. We report here the application of small ubiquitin-related
modifier (SUMO) fusion technology to the expression and purification of cationic antibacterial peptide ABP-CM4. The fusion
protein expressed in a soluble form was purified to a purity of 90% by Ni-IDA chromatography and 112 mg protein of interest
was obtained per liter of fermentation culture. After the SUMO–CM4 fusion protein was cleaved by the SUMO protease at 30 °C
for 1 h, the cleaved sample was re-applied to a Ni-IDA. Finally, about 24 mg recombinant CM4 was obtained from 1 l fermentation
culture with no less than 96% purity and the recombinant CM4 had similar antimicrobial properties to the synthetic CM4. Thus,
the SUMO-mediated peptide expression and purification system potentially could be employed for the production of recombinant
cytotoxic peptides. 相似文献
13.
Lei Huang Susanna Su Jan Leong Rongrong Jiang 《Applied microbiology and biotechnology》2009,84(2):301-308
This study reports the first successful recombinant expression of cationic antimicrobial peptides human beta-defensin-26 and
human beta-defensin-27 in Escherichia coli. HBD26 and HBD27 genes were synthesized through codon optimization, and each gene was then cloned into the expression vector
pET32, which feature fusion protein thioredoxin at the N-terminal. The recombinant plasmids were then transformed into E. coli BL21 (DE3) and cultured in MBL medium, which gave yields of HBD26 and HBD27 fusion proteins of up to 1.38 and 1.29 g l−1, respectively. Affinity chromatography was used to purify the soluble fusion proteins, and the N-terminal TrxA tags were
cleaved off by enterokinase. Pure HBD26 and HBD27 were then obtained by cationic exchange chromatography. The overall recovery
of HBD26 was 38% and that of HBD27 reached 36%. Both variants showed salt-sensitive antimicrobial activity against gram-negative
E. coli but not against gram-positive Staphylococcus aureus and Saccharomyces cerevisiae. 相似文献
14.
Immunoaffinity chromatography is a powerful method for purification of proteins because of the high selectivity and avidity
of antibodies. Due to the strength of antigen–antibody binding, however, elution of proteins bound to antibodies that are
covalently immobilized on the column is performed by temporary denaturation of the antibody. Therefore, the development of
milder elution conditions could improve the recovery of the antibodies and prolong the life of the immunoaffinity column.
We describe the design and construction of an antibody that changes its affinity in response to external stimuli. The heavy
chain and light chain of a single chain Fv of the D1.3 antibody against hen egg-white lysozyme (HEL) were fused at the N- and C-termini, respectively, of the calmodulin-M13 fusion protein. The affinity of this fusion protein for HEL could be modulated
by changing the Ca2+ concentration. 相似文献
15.
The abundance of lysozyme on mucosal surfaces suggests that successful colonizers must be able to evade its antimicrobial effects. Lysozyme has a muramidase activity that hydrolyzes bacterial peptidoglycan and a non-muramidase activity attributable to its function as a cationic antimicrobial peptide. Two enzymes (PgdA, a N-acetylglucosamine deacetylase, and Adr, an O-acetyl transferase) that modify different sites on the peptidoglycan of Streptococcus pneumoniae have been implicated in its resistance to lysozyme in vitro. Here we show that the antimicrobial effect of human lysozyme is due to its muramidase activity and that both peptidoglycan modifications are required for full resistance by pneumococci. To examine the contribution of lysozyme and peptidoglycan modifications during colonization of the upper respiratory tract, competition experiments were performed with wild-type and pgdAadr mutant pneumococci in lysozyme M-sufficient (LysM+/+) and -deficient (LysM−/−) mice. The wild-type strain out-competed the double mutant in LysM+/+, but not LysM−/− mice, indicating the importance of resistance to the muramidase activity of lysozyme during mucosal colonization. In contrast, strains containing single mutations in either pgdA or adr prevailed over the wild-type strain in both LysM+/+ and LysM−/− mice. Our findings demonstrate that individual peptidoglycan modifications diminish fitness during colonization. The competitive advantage of wild-type pneumococci in LysM+/+ but not LysM−/− mice suggests that the combination of peptidoglycan modifications reduces overall fitness, but that this is outweighed by the benefits of resistance to the peptidoglycan degrading activity of lysozyme. 相似文献
16.
In this paper, we report on a catanionic vesicles-based strategy to reduce the cytotoxicity of the diacyl glycerol arginine-based
synthetic surfactants 1,2-dimyristoyl-rac-glycero-3-O-(N
α-acetyl-l-arginine) hydrochloride (1414RAc) and 1,2-dilauroyl-rac-glycero-3-O-(N
α-acetyl-l-arginine) hydrochloride (1212RAc). The behavior of these surfactants was studied either as pure components or after their
formulation as pseudo-tetra-chain catanionic mixtures with phosphatidylglycerol (PG) and as cationic mixtures with 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) used as control. The antimicrobial activity of the negatively charged formulations against
Acinetobacter baumannii was maintained with respect to the surfactant alone, while a significant improvement of the antimicrobial activity against
Staphylococcus aureus was observed, together with a strong decrease of hemolytic activity. The influence of the net charge of the catanionic vesicles
on membrane selectivity was studied using model membranes. The dynamics of surface tension changes induced by the addition
of 1414RAc/PG aqueous dispersions into phospholipid monolayers composed of zwitterionic DPPC as model system for mammalian
membranes and of negatively charged PG mimicking cytoplasmic membrane of Gram-positive bacteria was followed by tensiometry.
Our results constitute a proof of principle that tuning formulation can reduce the cytotoxicity of many surfactants, opening
their possible biological applications. 相似文献
17.
Filtered proteins including the low-molecular-weight protein lysozyme are reabsorbed by the proximal tubule via adsorptive endocytosis. This process starts with binding of the protein to the brush-border membrane. The binding of 125I-labelled egg-white lysozyme (EC 3.2.1.17) to isolated brush-border membranes of rat kidney and the effect of several low-molecular weight proteins on that binding was determined. The Scatchard plot revealed a one-component binding type with a dissociation constant of 5.3 μM and 53.0 nmol/mg membrane protein for the number of binding sites. The binding of the cationic lysozyme was inhibited competitively by the addition of cationic cytochrome c to the incubation medium, while the neutral myoglobin had no effect. The anionic β-lactoglobulin A inhibited the lysozyme binding in a noncompetitive manner. These data suggest that the binding takes place between positively charged groups of the protein molecule and negative sites on the brush-border membrane, and, the competition between the cationic cytochrome c and the cationic lysozyme for the binding sites may be responsible for the inhibitory effect of cytochrome c on renal lysozyme reabsorption. The binding step at the brush-border membrane appears to be cation-selective. 相似文献
18.
Structural evidence for lack of inhibition of fish goose-type lysozymes by a bacterial inhibitor of lysozyme 总被引:2,自引:0,他引:2
It is known that bacteria contain inhibitors of lysozyme activity. The recently discovered Escherichia coli inhibitor of vertebrate lysozyme (Ivy) and its potential interactions with several goose-type (g-type) lysozymes from fish
were studied using functional enzyme assays, comparative homology modelling, protein–protein docking, and molecular dynamics
simulations. Enzyme assays carried out on salmon g-type lysozyme revealed a lack of inhibition by Ivy. Detailed analysis of the complexes formed between Ivy and both hen egg
white lysozyme (HEWL) and goose egg white lysozyme (GEWL) suggests that electrostatic interactions make a dominant contribution
to inhibition. Comparison of three dimensional models of aquatic g-type lysozymes revealed important insertions in the β domain, and specific sequence substitutions yielding altered electrostatic
surface properties and surface curvature at the protein–protein interface. Thus, based on structural homology models, we propose
that Ivy is not effective against any of the known fish g-type lysozymes. Docking studies suggest a weaker binding mode between
Ivy and GEWL compared to that with HEWL, and our models explain the mechanistic necessity for conservation of a set of residues
in g-type lysozymes as a prerequisite for inhibition by Ivy. 相似文献
19.
Lactoferricin B (LfcinB), a 25 residue peptide derived from the N-terminal of bovine lactoferrin (bLF), causes depolarization
of the cytoplasmic membrane in susceptible bacteria. Its mechanism of action, however, still needs to be elucidated. In the
present study, synthetic LfcinB (without a disulfide bridge) and LfcinB (C–C; with a disulfide bridge) as well as three derivatives
with 15-, 11- and 9-residue peptides were prepared to investigate their antimicrobial nature and mechanisms. The antimicrobial
properties were measured via minimum inhibitory concentration (MIC) determinations, killing kinetics assays and synergy testing,
and hemolytic activities were assessed by hemoglobin release. Finally, the morphology of peptide-treated bacteria was determined
by atomic force microscopy (AFM). We found that there was no difference in MICs between LfcinB and LfcinB (C–C). Among the
derivatives, only LfcinB15 maintained nearly the same level as LfcinB, in the MIC range of 16–128 μg/ml, and the MICs of LfcinB11
(64–256 μg/ml) were 4 times more than LfcinB, while LfcinB9 exhibited the lowest antimicrobial activity. When treated at MIC
for 1 h, many blebs were formed and holes of various sizes appeared on the cell surface, but the cell still maintained its
integrity. This suggested that LfcinB had a major permeability effect on the cytoplasmic membrane of both Gram-positive and
Gram-negative bacteria, which also indicated it may be a possible intracellular target. Among the tested antibiotics, aureomycin
increased the bactericidal activity of LfcinB against E. coli, S. aureus and P. aeruginosa, but neomycin did not have such an effect. We also found that the combination of cecropin A and LfcinB had synergistic effects
against E. coli. 相似文献
20.
Benjamin Fränzel Christian Frese Maya Penkova Nils Metzler-Nolte Julia E. Bandow Dirk Andreas Wolters 《Journal of biological inorganic chemistry》2010,15(8):1293-1303
Multiresistant bacteria are becoming more and more widespread. It is therefore necessary to have new compound groups in hand,
such as small cationic peptides, to cope with these challenges. In this work, we present a comprehensive approach by monitoring
protein expression profiles in a Gram-positive bacterium (Corynebacterium glutamicum) to investigate the cellular response to such a compound, a ferrocene-conjugated arginine- and tryptophan-rich pentapeptide.
To achieve this, a proteomic outline was performed where the compound-treated sample was compared with an untreated control.
This study comprises more than 900 protein identifications, including numerous integral membrane proteins, and among these
185 differential expressions. Surprisingly, unregulated catalase and no elevated H2O2 levels demonstrate that no oxidative stress occurs after treatment with the iron-containing compound as a consequence of
the potential Fenton reaction. A sufficient iron supply is evidenced by the iron-containing protein aconitase and SufB (the
latter belongs to an iron–sulfur cluster assembly system) and decreased levels of ATP-binding-cassette-type cobalamin/Fe3+ siderophore transporters. The organometallic peptide antibiotic targets the cell membrane, which is evident by decreased
levels of various integral membrane proteins, such as peptide permeases and transporters, and an altered lipid composition.
Conversion to a more rigid cell membrane seems to be a relevant protective strategy of C. glutamicum against the ferrocene-conjugated antimicrobial peptide compound. 相似文献