1
|
Zhu S, Kachooei E, Harmer JR, Brown LJ, Separovic F, Sani MA. TOAC spin-labeled peptides tailored for DNP-NMR studies in lipid membrane environments. Biophys J 2021; 120:4501-4511. [PMID: 34480924 DOI: 10.1016/j.bpj.2021.08.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 07/08/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022] Open
Abstract
The benefit of combining in-cell solid-state dynamic nuclear polarization (DNP) NMR and cryogenic temperatures is providing sufficient signal/noise and preservation of bacterial integrity via cryoprotection to enable in situ biophysical studies of antimicrobial peptides. The radical source required for DNP was delivered into cells by adding a nitroxide-tagged peptide based on the antimicrobial peptide maculatin 1.1 (Mac1). In this study, the structure, localization, and signal enhancement properties of a single (T-MacW) and double (T-T-MacW) TOAC (2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid) spin-labeled Mac1 analogs were determined within micelles or lipid vesicles. The solution NMR and circular dichroism results showed that the spin-labeled peptides adopted helical structures in contact with micelles. The peptides behaved as an isolated radical source in the presence of multilamellar vesicles, and the electron paramagnetic resonance (EPR) electron-electron distance for the doubly spin-labeled peptide was ∼1 nm. The strongest paramagnetic relaxation enhancement (PRE) was observed for the lipid NMR signals near the glycerol-carbonyl backbone and was stronger for the doubly spin-labeled peptide. Molecular dynamics simulation of the T-T-MacW radical source in phospholipid bilayers supported the EPR and PRE observations while providing further structural insights. Overall, the T-T-MacW peptide achieved better 13C and 15N signal NMR enhancements and 1H spin-lattice T1 relaxation than T-MacW.
Collapse
Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Ehsan Kachooei
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
| | - Louise J Brown
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia.
| |
Collapse
|
2
|
Zhu S, Li W, O'Brien-Simpson N, Separovic F, Sani MA. C-terminus amidation influences biological activity and membrane interaction of maculatin 1.1. Amino Acids 2021; 53:769-777. [PMID: 33891157 DOI: 10.1007/s00726-021-02983-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/16/2021] [Indexed: 11/24/2022]
Abstract
Cationic antimicrobial peptides have been investigated for their potential use in combating infections by targeting the cell membrane of microbes. Their unique chemical structure has been investigated to understand their mode of action and optimize their dose-response by rationale design. One common feature among cationic AMPs is an amidated C-terminus that provides greater stability against in vivo degradation. This chemical modification also likely modulates the interaction with the cell membrane of bacteria yet few studies have been performed comparing the effect of the capping groups. We used maculatin 1.1 (Mac1) to assess the role of the capping groups in modulating the peptide bacterial efficiency, stability and interactions with lipid membranes. Circular dichroism results showed that C-terminus amidation maintains the structural stability of the peptide (α-helix) in contact with micelles. Dye leakage experiments revealed that amidation of the C-terminus resulted in higher membrane disruptive ability while bacteria and cell viability assays revealed that the amidated form displayed higher antibacterial ability and cytotoxicity compared to the acidic form of Mac1. Furthermore, 31P and 2H solid-state NMR showed that C-terminus amidation played a greater role in disturbance of the phospholipid headgroup but had little effect on the lipid tails. This study paves the way to better understand how membrane-active AMPs act in live bacteria.
Collapse
Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Wenyi Li
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Neil O'Brien-Simpson
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
| |
Collapse
|
3
|
Zhu S, Weber DK, Separovic F, Sani MA. Expression and purification of the native C-amidated antimicrobial peptide maculatin 1.1. J Pept Sci 2021; 27:e3330. [PMID: 33843136 DOI: 10.1002/psc.3330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/09/2022]
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide (AMP) from an Australian tree frog and exhibits low micromolar activity against Gram-positive bacteria. The antimicrobial properties of Mac1 are linked to its disruption of bacterial lipid membranes, which has been studied extensively by in vitro nuclear magnetic resonance (NMR) spectroscopy and biophysical approaches. Although in vivo NMR has recently proven effective in probing peptide-lipid interplay in live bacterial cells, direct structural characterisation of AMPs has been prohibited by low sensitivity and overwhelming background noise. To overcome this issue, we report a recombinant expression protocol to produce isotopically enriched Mac1. We utilized a double-fusion construct to alleviate toxicity against the Escherichia coli host and generate the native N-free and C-amidated termini Mac1 peptide. The SUMO and intein tags allowed native N-terminus and C-terminal amidation, respectively, to be achieved in a one-pot reaction. The protocol yielded 0.1 mg/L of native, uniformly 15 N-labelled, Mac1, which possessed identical structure and activity to peptide obtained by solid-phase peptide synthesis.
Collapse
Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Daniel K Weber
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
4
|
Wang T, Ni G, Furushima T, Diao H, Zhang P, Chen S, Fogarty CE, Jiang Z, Liu X, Li H. Mg alloy surface immobilised with caerin peptides acquires enhanced antibacterial ability and putatively improved corrosion resistance. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 121:111819. [PMID: 33579462 DOI: 10.1016/j.msec.2020.111819] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 01/04/2023]
Abstract
Magnesium (Mg) has mechanical properties similar to human bones and Mg alloy is considered ideal medical implant material. However, the high velocity of degradation inside the human inner environment severely hampers the usage of Mg alloys. In this study, caerin peptide 1.9 (F3) and a modified sequence of caerin 1.1 (F1) with anti-bacterial activity, were covalently immobilised on the surface of Mg alloys by plasma chemical click reaction. The in vitro antibacterial activity and corrosion resistance of these caerin peptide-immobilised Mg alloys were investigated in Dulbecco's Modified Eagle Medium (DMEM) solution. Un-immobilised Mg alloy sample, blank drug-sensitive tablet (BASD) and a commonly used antibiotics Tazocin were used for comparison. Results showed that peptide immobilised Mg samples showed observable improved corrosion resistance and prolonged antibacterial effect compared to non-immobilised Mg alloy and free caerin peptides. These results indicate that coating Mg alloy with caerin peptides obviously increases the alloy's antibacterial ability and putatively improves the corrosion resistance in vitro. The mechanism underlying the prolonged antibacterial effect for annealed Mg alloys immobilised with the peptides (especially F3) remains unclear, which worth further experimental and theoretical investigation.
Collapse
Affiliation(s)
- Tianfang Wang
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia
| | - Guoying Ni
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia; The First Affiliated Hospital/School of Clinical Medicine of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - Tsuyoshi Furushima
- Institute of Industrial Science, Department of Mechanical and Biofunctional Systems, The University of Tokyo, 4-6-1, Komaba, Meguro, Tokyo 153-8505, Japan
| | - Hui Diao
- Centre for Microscopy and Microanalysis, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Pingping Zhang
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Shu Chen
- Cancer Research Institute, First People's Hospital of Foshan, Foshan, Guangdong 528000, China
| | - Conor E Fogarty
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia
| | - Zhengyi Jiang
- School of Mechanical, Materials, Mechatronic and Biomedical Engineering, Faculty of Engineering and Information Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW 2522, Australia
| | - Xiaosong Liu
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia; Cancer Research Institute, First People's Hospital of Foshan, Foshan, Guangdong 528000, China.
| | - Hejie Li
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia; Institute of Industrial Science, Department of Mechanical and Biofunctional Systems, The University of Tokyo, 4-6-1, Komaba, Meguro, Tokyo 153-8505, Japan.
| |
Collapse
|
5
|
Le Brun AP, Zhu S, Sani MA, Separovic F. The Location of the Antimicrobial Peptide Maculatin 1.1 in Model Bacterial Membranes. Front Chem 2020; 8:572. [PMID: 32733854 PMCID: PMC7358649 DOI: 10.3389/fchem.2020.00572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022] Open
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide (AMP) from the skin secretions of Australian tree frogs. In this work, the interaction of Mac1 with anionic phospholipid bilayers was investigated by NMR, circular dichroism (CD) spectroscopy, neutron reflectometry (NR) and molecular dynamics (MD). In buffer, the peptide is unstructured but in the presence of anionic (DPC/LMPG) micelles or (DMPC/DMPG/DHPC) bicelles adopts a helical structure. Addition of the soluble paramagnetic agent gadolinium (Gd-DTPA) into the Mac1-DPC/LMPG micelle solution showed that the N-terminus is more exposed to the hydrophilic Gd-DTPA than the C-terminus in micelles. 2H and 31P solid-state NMR showed that Mac1 had a greater effect on the anionic lipid (DMPG). A deuterium labeled Mac1 used in NR experiments indicated that the AMP spanned across anionic (PC/PG) bilayers, which was compatible with MD simulations. Simulations also showed that Mac1 orientation remained transmembrane in bilayers and wrapped on the surface of the micelles regardless of the lipid or detergent charge. Thus, the peptide orientation appears to be more susceptible to curvature than charged surface. These results support the formation of transmembrane pores by Mac1 in model bacterial membranes.
Collapse
Affiliation(s)
- Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, NSW, Australia
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| |
Collapse
|
6
|
Sani MA, Le Brun AP, Separovic F. The antimicrobial peptide maculatin self assembles in parallel to form a pore in phospholipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183204. [DOI: 10.1016/j.bbamem.2020.183204] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/15/2019] [Accepted: 01/21/2020] [Indexed: 01/06/2023]
|
7
|
Overall SA, Zhu S, Hanssen E, Separovic F, Sani MA. In Situ Monitoring of Bacteria under Antimicrobial Stress Using 31P Solid-State NMR. Int J Mol Sci 2019; 20:ijms20010181. [PMID: 30621328 PMCID: PMC6337522 DOI: 10.3390/ijms20010181] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/25/2018] [Accepted: 01/01/2019] [Indexed: 11/23/2022] Open
Abstract
In-cell NMR offers great insight into the characterization of the effect of toxins and antimicrobial peptides on intact cells. However, the complexity of intact live cells remains a significant challenge for the analysis of the effect these agents have on different cellular components. Here we show that 31P solid-state NMR can be used to quantitatively characterize the dynamic behaviour of DNA within intact live bacteria. Lipids were also identified and monitored, although 31P dynamic filtering methods indicated a range of dynamic states for phospholipid headgroups. We demonstrate the usefulness of this methodology for monitoring the activity of the antibiotic ampicillin and the antimicrobial peptide (AMP) maculatin 1.1 (Mac1.1) against Gram-negative bacteria. Perturbations in the dynamic behaviour of DNA were observed in treated cells, which indicated additional mechanisms of action for the AMP Mac1.1 not previously reported. This work highlights the value of 31P in-cell solid-state NMR as a tool for assessing the antimicrobial activity of antibiotics and AMPs in bacterial cells.
Collapse
Affiliation(s)
- Sarah A Overall
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
- Chemistry & Biochemistry Department, UC Santa Cruz, CA 95064, USA.
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Eric Hanssen
- Advanced Microscopy Facility and Department of Biochemistry & Molecular Biology, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| |
Collapse
|
8
|
Balatti GE, Martini MF, Pickholz M. A coarse-grained approach to studying the interactions of the antimicrobial peptides aurein 1.2 and maculatin 1.1 with POPG/POPE lipid mixtures. J Mol Model 2018; 24:208. [PMID: 30019106 DOI: 10.1007/s00894-018-3747-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/27/2018] [Indexed: 01/08/2023]
Abstract
In the present work we investigated the differential interactions of the antimicrobial peptides (AMPs) aurein 1.2 and maculatin 1.1 with a bilayer composed of a mixture of the lipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE). We carried out molecular dynamics (MD) simulations using a coarse-grained approach within the MARTINI force field. The POPE/POPG mixture was used as a simple model of a bacterial (prokaryotic cell) membrane. The results were compared with our previous findings for structures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), a representative lipid of mammalian cells. We started the simulations of the peptide-lipid system from two different initial conditions: peptides in water and peptides inside the hydrophobic core of the membrane, employing a pre-assembled lipid bilayer in both cases. Our results show similarities and differences regarding the molecular behavior of the peptides in POPE/POPG in comparison to their behavior in a POPC membrane. For instance, aurein 1.2 molecules can adopt similar pore-like structures on both POPG/POPE and POPC membranes, but the peptides are found deeper in the hydrophobic core in the former. Maculatin 1.1 molecules, in turn, achieve very similar structures in both kinds of bilayers: they have a strong tendency to form clusters and induce curvature. Therefore, the results of this study provide insight into the mechanisms of action of these two peptides in membrane leakage, which allows organisms to protect themselves against potentially harmful bacteria. Graphical Abstract Aurein pore structure (green) in a lipid bilayer composed by POPE (blue) and POPG (red) mixture. It is possible to see water beads (light blue) inside the pore.
Collapse
Affiliation(s)
- G E Balatti
- Facultad de Ciencias Exactas y Naturales, Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, IFIBA, C1428BFA, Buenos Aires, Argentina
| | - M F Martini
- Facultad de Farmacia y Bioquímica, Departamento de Farmacología, Universidad de Buenos Aires, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, IQUIMEFA, C1113AA, Buenos Aires, Argentina
| | - M Pickholz
- Facultad de Ciencias Exactas y Naturales, Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina. .,CONICET-Universidad de Buenos Aires, IFIBA, C1428BFA, Buenos Aires, Argentina.
| |
Collapse
|
9
|
Gomes KAGG, Dos Santos DM, Santos VM, Piló-Veloso D, Mundim HM, Rodrigues LV, Lião LM, Verly RM, de Lima ME, Resende JM. NMR structures in different membrane environments of three ocellatin peptides isolated from Leptodactylus labyrinthicus. Peptides 2018; 103:72-83. [PMID: 29596881 DOI: 10.1016/j.peptides.2018.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
The peptides ocellatin-LB1, -LB2 and -F1 have previously been isolated from anurans of the Leptodactylus genus and the sequences are identical from residue 1-22, which correspond to ocellatin-LB1 sequence (GVVDILKGAAKDIAGHLASKVM-NH2), whereas ocellatin-LB2 carries an extra N and ocellatin-F1 extra NKL residues at their C-termini. These peptides showed different spectra of activities and biophysical investigations indicated a direct correlation between membrane-disruptive properties and antimicrobial activities, i.e. ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. To better characterize their membrane interactions, we report here the detailed three-dimensional NMR structures of these peptides in TFE-d2:H2O (60:40) and in the presence of zwitterionic DPC-d38 and anionic SDS-d25 micellar solutions. Although the three peptides showed significant helical contents in the three mimetic environments, structural differences were noticed. When the structures of the three peptides in the presence of DPC-d38 micelles are compared to each other, a more pronounced curvature is observed for ocellatin-F1 and the bent helix, with the concave face composed mostly of hydrophobic residues, is consistent with the micellar curvature and the amphipathic nature of the molecule. Interestingly, an almost linear helical segment was observed for ocellatin-F1 in the presence of SDS-d25 micelles and the conformational differences in the two micellar environments are possibly related to the presence of the extra Lys residue near the peptide C-terminus, which increases the affinity of ocellatin-F1 to anionic membranes in comparison with ocellatin-LB1 and -LB2, as proved by isothermal titration calorimetry. To our knowledge, this work reports for the first time the three-dimensional structures of ocellatin peptides.
Collapse
Affiliation(s)
- Karla A G G Gomes
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil; Instituto de Engenharia, Ciência e Tecnologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39440-000 Janaúba, MG, Brazil
| | - Daniel M Dos Santos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Virgílio M Santos
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Dorila Piló-Veloso
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Higor M Mundim
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Leticia V Rodrigues
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Luciano M Lião
- Instituto de Química, Universidade Federal de Goiás, Av. Esperança, s/n, Campus Samambaia, 74690-900 Goiânia, GO, Brazil
| | - Rodrigo M Verly
- Departamento de Química, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39100-000 Diamantina, MG, Brazil
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil
| | - Jarbas M Resende
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, 31270-901 Belo Horizonte, MG, Brazil.
| |
Collapse
|
10
|
Lee TH, Sani MA, Overall S, Separovic F, Aguilar MI. Effect of phosphatidylcholine bilayer thickness and molecular order on the binding of the antimicrobial peptide maculatin 1.1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:300-309. [DOI: 10.1016/j.bbamem.2017.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/18/2017] [Accepted: 10/08/2017] [Indexed: 01/01/2023]
|
11
|
Lee MR, Raman N, Gellman SH, Lynn DM, Palecek SP. Incorporation of β-Amino Acids Enhances the Antifungal Activity and Selectivity of the Helical Antimicrobial Peptide Aurein 1.2. ACS Chem Biol 2017; 12:2975-2980. [PMID: 29091404 DOI: 10.1021/acschembio.7b00843] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antimicrobial peptides (AMPs) are attractive antifungal drug candidates because they kill microbes via membrane disruption and are thus unlikely to provoke development of resistance. Low selectivity for fungal vs human cells and instability in physiological environments have limited the development of AMPs as therapeutics, but peptidomimetic AMPs can overcome these obstacles and also provide useful insight into AMP structure-function relationships. Here, we describe antifungal peptidomimetic α/β-peptides templated on the natural α-peptidic AMP aurein 1.2. These α/β-aurein analogs fold into i → i + 4 H-bonded helices that present arrays of side chain functionality in a manner virtually identical to that of aurein 1.2. By varying charge, hydrophobicity, conformational stability, and α/β-amino acid organization, we designed active and selective α/β-peptide aurein analogs that exhibit minimum inhibitory concentrations (MIC) against the opportunistic pathogen Candida albicans that are 4-fold lower than that of aurein 1.2 and elicit less than 5% hemolysis at the MIC. These α/β-aurein analogs are promising candidates for development as antifungal therapeutics and as tools to elucidate mechanisms of AMP activity and specificity.
Collapse
Affiliation(s)
- Myung-Ryul Lee
- Department
of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Namrata Raman
- Department
of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department
of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - David M. Lynn
- Department
of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Sean P. Palecek
- Department
of Chemical and Biological Engineering and ‡Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
12
|
Sani MA, Separovic F. Antimicrobial Peptide Structures: From Model Membranes to Live Cells. Chemistry 2017; 24:286-291. [PMID: 29068097 DOI: 10.1002/chem.201704362] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Indexed: 01/12/2023]
Abstract
The rise in antibiotic resistance has led to a renewed interest in antimicrobial peptides (AMPs) that target membranes. The mode of action of AMPs involves the disruption of the lipid bilayer and leads to growth inhibition and death of the bacteria. However, details at the molecular level of how these peptides kill bacteria and the reasons for the observed differences in selectivity remain unclear. Structural information is crucial for defining the molecular mechanism by which these peptides recognize, self-assemble and interact with a particular lipid membrane. Solid-state NMR is a non-invasive technique that allows the study of the structural details of lipid-peptide and peptide-peptide interactions. Following on from studies of antibiotic and lytic peptides, gramicidin A and melittin, respectively, we investigated maculatin 1.1, an AMP from the skin of Australian tree frogs that acts against Gram-positive bacteria. By using perdeuterated phospholipids and specifically labelled peptides, 2 H, 31 P and {31 P}15 N REDOR solid-state NMR experiments have been used to localize, maculatin 1.1 in neutral and anionic model membranes. However, the structure, location and activity depend on the composition of the model membrane and current advances in solid-state NMR spectroscopy now allow structure determination of AMPs in live bacteria.
Collapse
Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| |
Collapse
|
13
|
Phenylalanine residues act as membrane anchors in the antimicrobial action of Aurein 1.2. Biointerphases 2017; 12:05G605. [PMID: 29078702 DOI: 10.1116/1.4995674] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aurein 1.2 is a small cationic antimicrobial peptide, one of the shortest peptides that can exert antimicrobial activity at low micromolar concentrations. Aurein 1.2 is a surface acting peptide, following the "carpet" mechanism of thresholded membrane disruption. It is generally assumed that the activity of such cationic α-helical membrane disrupting peptides is charge driven. Here, the authors show that instead of charge interactions, aromatic phenylalanine residues of the Aurein 1.2 sequence facilitate the membrane binding. The activity of the wild type peptide was compared to mutants in which the Phe residues were substituted, singly and in tandem, with alanine. Measurements by quartz crystal microbalance, impedance spectroscopy, and dye leakage experiments demonstrated that single residue mutants retain a much-reduced activity whereas the deletion of both Phe residues prevents membrane disruption entirely. The single residue mutants exhibited an altered mechanism of action, permeabilizing but not dissolving the target membranes. These results offer a new design rule for membrane disrupting peptides with potential pharmacological applications.
Collapse
|
14
|
Differential Interaction of Antimicrobial Peptides with Lipid Structures Studied by Coarse-Grained Molecular Dynamics Simulations. Molecules 2017; 22:molecules22101775. [PMID: 29053635 PMCID: PMC6151434 DOI: 10.3390/molecules22101775] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/17/2017] [Indexed: 01/05/2023] Open
Abstract
In this work; we investigated the differential interaction of amphiphilic antimicrobial peptides with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid structures by means of extensive molecular dynamics simulations. By using a coarse-grained (CG) model within the MARTINI force field; we simulated the peptide-lipid system from three different initial configurations: (a) peptides in water in the presence of a pre-equilibrated lipid bilayer; (b) peptides inside the hydrophobic core of the membrane; and (c) random configurations that allow self-assembled molecular structures. This last approach allowed us to sample the structural space of the systems and consider cooperative effects. The peptides used in our simulations are aurein 1.2 and maculatin 1.1; two well-known antimicrobial peptides from the Australian tree frogs; and molecules that present different membrane-perturbing behaviors. Our results showed differential behaviors for each type of peptide seen in a different organization that could guide a molecular interpretation of the experimental data. While both peptides are capable of forming membrane aggregates; the aurein 1.2 ones have a pore-like structure and exhibit a higher level of organization than those conformed by maculatin 1.1. Furthermore; maculatin 1.1 has a strong tendency to form clusters and induce curvature at low peptide-lipid ratios. The exploration of the possible lipid-peptide structures; as the one carried out here; could be a good tool for recognizing specific configurations that should be further studied with more sophisticated methodologies.
Collapse
|
15
|
Pillong M, Hiss JA, Schneider P, Lin YC, Posselt G, Pfeiffer B, Blatter M, Müller AT, Bachler S, Neuhaus CS, Dittrich PS, Altmann KH, Wessler S, Schneider G. Rational Design of Membrane-Pore-Forming Peptides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1701316. [PMID: 28799716 DOI: 10.1002/smll.201701316] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/29/2017] [Indexed: 06/07/2023]
Abstract
Specific interactions of peptides with lipid membranes are essential for cellular communication and constitute a central aspect of the innate host defense against pathogens. A computational method for generating innovative membrane-pore-forming peptides inspired by natural templates is presented. Peptide representation in terms of sequence- and topology-dependent hydrophobic moments is introduced. This design concept proves to be appropriate for the de novo generation of first-in-class membrane-active peptides with the anticipated mode of action. The designed peptides outperform the natural template in terms of their antibacterial activity. They form a kinked helical structure and self-assemble in the membrane by an entropy-driven mechanism to form dynamically growing pores that are dependent on the lipid composition. The results of this study demonstrate the unique potential of natural template-based peptide design for chemical biology and medicinal chemistry.
Collapse
Affiliation(s)
- Max Pillong
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Jan A Hiss
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Petra Schneider
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Yen-Chu Lin
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Gernot Posselt
- Department of Molecular Biology, University of Salzburg, 5020, Salzburg, Austria
| | - Bernhard Pfeiffer
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Markus Blatter
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Alex T Müller
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Simon Bachler
- Department of Biosystems Science and Engineering, ETH Zurich, 8093, Zurich, Switzerland
| | - Claudia S Neuhaus
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, ETH Zurich, 8093, Zurich, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Silja Wessler
- Department of Molecular Biology, University of Salzburg, 5020, Salzburg, Austria
| | - Gisbert Schneider
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| |
Collapse
|
16
|
Jeon D, Jeong MC, Jacob B, Bang JK, Kim EH, Cheong C, Jung ID, Park Y, Kim Y. Investigation of cationicity and structure of pseudin-2 analogues for enhanced bacterial selectivity and anti-inflammatory activity. Sci Rep 2017; 7:1455. [PMID: 28469145 PMCID: PMC5431190 DOI: 10.1038/s41598-017-01474-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/28/2017] [Indexed: 12/14/2022] Open
Abstract
Pseudin-2 (Ps), isolated from the frog Pseudis paradoxa, exhibits potent antibacterial activity and cytotoxicity. To develop antimicrobial peptides with anti-inflammatory activity and low cytotoxicity, we designed Ps analogues with Lys substitutions, resulting in elevated amphipathic α-helical structure and cationicity. We further substituted Gly11 with Pro (Ps-P analogues) to increase bacterial cell selectivity. Ps analogues retained antimicrobial activity and exhibited reduced cytotoxicity, whereas Ps-P analogues exhibited lower cytotoxicity and antimicrobial activity. Tertiary structures revealed that Ps has a linear α-helix from Leu2 to Glu24, whereas Ps-P has a bend at Pro11 between two short α-helixes. Using various biophysical experiments, we found that Ps analogues produced much higher membrane depolarization than Ps-P analogues, whereas Ps-P analogues may penetrate bacterial cell membranes. Ps and its analogue Ps-K18 exhibited potent anti-inflammatory activity in LPS-stimulated RAW264.7 and mouse dendritic cells via a mechanism involving the Toll-like receptor 4 (TLR4) pathway. These activities may arise from their direct inhibition of the formation of TLR4-MD-2_LPS complex, implying that amphipathic α-helical structure with an optimum balance between enhanced cationicity and hydrophobicity may be essential for their anti-inflammatory activity. The bent structure provided by Pro substitution plays an important role in enhancing bacterial cell selectivity and cell penetration.
Collapse
Affiliation(s)
- Dasom Jeon
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Korea
| | - Min-Cheol Jeong
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Korea
| | - Binu Jacob
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Korea
| | - Jeong Kyu Bang
- Division of Magnetic Resonance, Korea Basic Science Institute, Ochang, 28119, Korea
| | - Eun-Hee Kim
- Division of Magnetic Resonance, Korea Basic Science Institute, Ochang, 28119, Korea
| | - Chaejoon Cheong
- Division of Magnetic Resonance, Korea Basic Science Institute, Ochang, 28119, Korea
| | - In Duk Jung
- Department of Immunology, Lab of Dendritic Cell Differentiation & Regulation, School of Medicine, Konkuk University, Chungju, 380-701, Korea
| | - Yoonkyung Park
- Department of Biomedical Science and Research Center for Proteinaceous Materials (RCPM), Chosun University, Gwangju, 61452, Korea
| | - Yangmee Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Korea.
| |
Collapse
|
17
|
Laadhari M, Arnold AA, Gravel AE, Separovic F, Marcotte I. Interaction of the antimicrobial peptides caerin 1.1 and aurein 1.2 with intact bacteria by 2 H solid-state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2959-2964. [DOI: 10.1016/j.bbamem.2016.09.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/11/2016] [Accepted: 09/12/2016] [Indexed: 11/17/2022]
|
18
|
Wang Y, Chen CH, Hu D, Ulmschneider MB, Ulmschneider JP. Spontaneous formation of structurally diverse membrane channel architectures from a single antimicrobial peptide. Nat Commun 2016; 7:13535. [PMID: 27874004 PMCID: PMC5121426 DOI: 10.1038/ncomms13535] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/12/2016] [Indexed: 12/29/2022] Open
Abstract
Many antimicrobial peptides (AMPs) selectively target and form pores in microbial membranes. However, the mechanisms of membrane targeting, pore formation and function remain elusive. Here we report an experimentally guided unbiased simulation methodology that yields the mechanism of spontaneous pore assembly for the AMP maculatin at atomic resolution. Rather than a single pore, maculatin forms an ensemble of structurally diverse temporarily functional low-oligomeric pores, which mimic integral membrane protein channels in structure. These pores continuously form and dissociate in the membrane. Membrane permeabilization is dominated by hexa-, hepta- and octamers, which conduct water, ions and small dyes. Pores form by consecutive addition of individual helices to a transmembrane helix or helix bundle, in contrast to current poration models. The diversity of the pore architectures—formed by a single sequence—may be a key feature in preventing bacterial resistance and could explain why sequence–function relationships in AMPs remain elusive. Antimicrobial peptides (AMPs) selectively form pores in microbial membranes in process not fully understood. Here the authors use experimentally guided molecular dynamics to study maculatin pore formation, showing how this AMP assembles into transient and structurally diverse oligomeric pores in cell membranes.
Collapse
Affiliation(s)
- Yukun Wang
- Institute of Natural Sciences, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China.,Department of Physics and Astronomy, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China.,Institute of NanoBioTechnology, Johns Hopkins University, 204C Schaffer Hall, 3400 North Charles Street, Baltimore, Maryland 21218-2681, USA
| | - Charles H Chen
- Institute of NanoBioTechnology, Johns Hopkins University, 204C Schaffer Hall, 3400 North Charles Street, Baltimore, Maryland 21218-2681, USA.,Department of Materials Science and Engineering, Johns Hopkins University, 204C Schaffer Hall, 3400 North Charles Street, Baltimore, Maryland 21218-2681, USA
| | - Dan Hu
- Institute of Natural Sciences, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China.,Department of Mathematics, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Martin B Ulmschneider
- Institute of NanoBioTechnology, Johns Hopkins University, 204C Schaffer Hall, 3400 North Charles Street, Baltimore, Maryland 21218-2681, USA.,Department of Materials Science and Engineering, Johns Hopkins University, 204C Schaffer Hall, 3400 North Charles Street, Baltimore, Maryland 21218-2681, USA
| | - Jakob P Ulmschneider
- Institute of Natural Sciences, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China.,Department of Physics and Astronomy, Shanghai Jiao-Tong University, 800 Dongchuan Road, Shanghai 200240, China
| |
Collapse
|
19
|
Abstract
The structure-function relationship for a family of antimicrobial peptides (AMPs) from the skin of Australian tree frogs is discussed and compared with that of peptide toxins from bee and Australian scorpion venoms. Although these membrane-active peptides induce a similar cellular fate by disrupting the lipid bilayer integrity, their lytic activity is achieved via different modes of action, which are investigated in relation to amino acid sequence, secondary structure, and membrane lipid composition. In order to better understand what structural features govern the interaction between peptides and lipid membranes, cell-penetrating peptides (CPPs), which translocate through the membrane without compromising its integrity, are also discussed. AMPs possess membrane lytic activities that are naturally designed to target the cellular membrane of pathogens or competitors. They are extremely diverse in amino acid composition and often show specificity against a particular strain of microbe. Since our antibiotic arsenal is declining precariously in the face of the rise in multiantibiotic resistance, AMPs increasingly are seen as a promising alternative. In an effort to understand their molecular mechanism, biophysical studies of a myriad of AMPs have been reported, yet no unifying mechanism has emerged, rendering difficult the rational design of drug leads. Similarly, a wide variety of cytotoxic peptides are found in venoms, the best known being melittin, yet again, predicting their activity based on a particular amino acid composition or secondary structure remains elusive. A common feature of these membrane-active peptides is their preference for the lipid environment. Indeed, they are mainly unstructured in solution and, in the presence of lipid membranes, quickly adsorb onto the surface, change their secondary structure, eventually insert into the hydrophobic core of the membrane bilayer, and finally disrupt the bilayer integrity. These steps define the molecular mechanism by which these membrane-active peptides lyse membranes. The last class of membrane-active peptides discussed are the CPPs, which translocate across the lipid bilayer without inducing severe disruption and have potential as drug vehicles. CPPs are typically highly charged and can show antimicrobial activity by targeting an intracellular target rather than via a direct membrane lytic mechanism. A critical aspect in the structure-function relationship of membrane-active peptides is their specific activity relative to the lipid membrane composition of the cell target. Cell membranes have a wide diversity of lipids, and those of eukaryotic and prokaryotic species differ greatly in composition and structure. The activity of AMPs from Australian tree frogs, toxins, and CPPs has been investigated within various lipid systems to assess whether a relationship between peptide and membrane composition could be identified. NMR spectroscopy techniques are being used to gain atomistic details of how these membrane-active peptides interact with model membranes and cells, and in particular, competitive assays demonstrate the difference between affinity and activity for a specific lipid environment. Overall, the interactions between these relatively small sized peptides and various lipid bilayers give insight into how these peptides function at the membrane interface.
Collapse
Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21
Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21
Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| |
Collapse
|
20
|
Antimicrobial activity, improved cell selectivity and mode of action of short PMAP-36-derived peptides against bacteria and Candida. Sci Rep 2016; 6:27258. [PMID: 27251456 PMCID: PMC4890124 DOI: 10.1038/srep27258] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/17/2016] [Indexed: 11/08/2022] Open
Abstract
Antimicrobial peptides (AMPs) have recently attracted a great deal of attention as promising antibiotic candidates, but some obstacles such as toxicity and high synthesis cost must be addressed before developing them further. For developing short peptides with improved cell selectivity, we designed a series of modified PMAP-36 analogues. Antimicrobial assays showed that decreasing chain length in a certain range retained the high antimicrobial activity of the parental peptide and reduced hemolysis. The 18-mer peptide RI18 exhibited excellent antimicrobial activity against both bacteria and fungi, and its hemolytic activity was observably lower than PMAP-36 and melittin. The selectivity indexes of RI18 against bacteria and fungi were improved approximately 19-fold and 108-fold, respectively, compared to PMAP-36. In addition, serum did not affect the antibacterial activity of RI18 against E. coli but inhibited the antifungal efficiency against C. albicans. Flow cytometry and electron microscopy observation revealed that RI18 killed microbial cells primarily by damaging membrane integrity, leading to whole cell lysis. Taken together, these results suggest that RI18 has potential for further therapeutic research against frequently-encountered bacteria and fungi. Meanwhile, modification of AMPs is a promising strategy for developing novel antimicrobials to overcome drug-resistance.
Collapse
|
21
|
Manzo G, Scorciapino MA, Srinivasan D, Attoub S, Mangoni ML, Rinaldi AC, Casu M, Flatt PR, Conlon JM. Conformational Analysis of the Host-Defense Peptides Pseudhymenochirin-1Pb and -2Pa and Design of Analogues with Insulin-Releasing Activities and Reduced Toxicities. JOURNAL OF NATURAL PRODUCTS 2015; 78:3041-3048. [PMID: 26606380 DOI: 10.1021/acs.jnatprod.5b00843] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Pseudhymenochirin-1Pb (Ps-1Pb; IKIPSFFRNILKKVGKEAVSLIAGALKQS) and pseudhymenochirin-2Pa (Ps-2Pa; GIFPIFAKLLGKVIKVASSLISKGRTE) are amphibian peptides with broad spectrum antimicrobial activities and cytotoxicity against mammalian cells. In the membrane-mimetic solvent 50% (v/v) trifluoroethanol-H2O, both peptides adopt a well-defined α-helical conformation that extends over almost all the sequence and incorporates a flexible bend. Both peptides significantly (p < 0.05) stimulate the rate of release of insulin from BRIN-BD11 clonal β-cells at concentrations ≥ 0.1 nM but produce loss of integrity of the plasma membrane at concentrations ≥ 1 μM. Increasing cationicity by the substitution Glu(17) → l-Lys in Ps-1Pb and Glu(27) → l-Lys in Ps-2Pa generates analogues with increased cytotoxicity and reduced insulin-releasing potency. In contrast, the analogues [R8r]Ps-1Pb and [K8k,K19k]Ps-2Pa, incorporating d-amino acid residues to destabilize the α-helical domains, retain potent insulin-releasing activity but are nontoxic to BRIN-BD11 cells at concentrations of 3 μM. [R8r]Ps-1Pb produces a significant increase in insulin release rate at 0.3 nM and [K8k,K19k]Ps-2Pa at 0.01 nM. Both analogues show low hemolytic activity (IC50 > 100 μM) but retain broad-spectrum antimicrobial activity and remain cytotoxic to a range of human tumor cell lines, albeit with lower potency than the naturally occurring peptides. These analogues show potential for development into agents for type 2 diabetes therapy.
Collapse
Affiliation(s)
| | | | - Dinesh Srinivasan
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster , Coleraine, BT52 1SA, U.K
| | - Samir Attoub
- Department of Pharmacology, College of Medicine and Health Sciences, United Arab Emirates University , 17666 Al Ain, United Arab Emirates
| | - Maria Luisa Mangoni
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome , 5 00185 Rome, Italy
| | | | | | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster , Coleraine, BT52 1SA, U.K
| | - J Michael Conlon
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster , Coleraine, BT52 1SA, U.K
| |
Collapse
|
22
|
Hayden RM, Goldberg GK, Ferguson BM, Schoeneck MW, Libardo MDJ, Mayeux SE, Shrestha A, Bogardus KA, Hammer J, Pryshchep S, Lehman HK, McCormick ML, Blazyk J, Angeles-Boza AM, Fu R, Cotten ML. Complementary Effects of Host Defense Peptides Piscidin 1 and Piscidin 3 on DNA and Lipid Membranes: Biophysical Insights into Contrasting Biological Activities. J Phys Chem B 2015; 119:15235-46. [DOI: 10.1021/acs.jpcb.5b09685] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert M. Hayden
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Gina K. Goldberg
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Bryan M. Ferguson
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Mason W. Schoeneck
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - M. Daben J. Libardo
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Sophie E. Mayeux
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Akritee Shrestha
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Kimberly A. Bogardus
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Janet Hammer
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Sergey Pryshchep
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Herman K. Lehman
- Department
of Biology, Hamilton College, Clinton, New York 13323, United States
| | | | - Jack Blazyk
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Alfredo M. Angeles-Boza
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Myriam L. Cotten
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| |
Collapse
|
23
|
Sani MA, Lee TH, Aguilar MI, Separovic F. Proline-15 creates an amphipathic wedge in maculatin 1.1 peptides that drives lipid membrane disruption. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2277-89. [DOI: 10.1016/j.bbamem.2015.06.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 11/28/2022]
|
24
|
Sani MA, Henriques ST, Weber D, Separovic F. Bacteria May Cope Differently from Similar Membrane Damage Caused by the Australian Tree Frog Antimicrobial Peptide Maculatin 1.1. J Biol Chem 2015; 290:19853-62. [PMID: 26100634 DOI: 10.1074/jbc.m115.643262] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022] Open
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide from the skin of Australian tree frogs and is known to possess selectivity toward Gram-positive bacteria. Although Mac1 has membrane disrupting activity, it is not known how Mac1 selectively targets Gram-positive over Gram-negative bacteria. The interaction of Mac1 with Escherichia coli, Staphylococcus aureus, and human red blood cells (hRBC) and with their mimetic model membranes is here reported. The peptide showed a 16-fold greater growth inhibition activity against S. aureus (4 μM) than against E. coli (64 μM) and an intermediate cytotoxicity against hRBC (30 μM). Surprisingly, Sytox Green uptake monitored by flow cytometry showed that Mac1 compromised both bacterial membranes with similar efficiency at ∼20-fold lower concentration than the reported minimum inhibition concentration against S. aureus. Mac1 also reduced the negative potential of S. aureus and E. coli membrane with similar efficacy. Furthermore, liposomes mimicking the cell membrane of S. aureus (POPG/TOCL) and E. coli (POPE/POPG) were lysed at similar concentrations, whereas hRBC-like vesicles (POPC/SM/Chol) remained mostly intact in the presence of Mac1. Remarkably, when POPG/TOCL and POPE/POPG liposomes were co-incubated, Mac1 did not induce leakage from POPE/POPG liposomes, suggesting a preference toward POPG/TOCL membranes that was supported by surface plasma resonance assays. Interestingly, circular dichroism spectroscopy showed a similar helical conformation in the presence of the anionic liposomes but not the hRBC mimics. Overall, the study showed that Mac1 disrupts bacterial membranes in a similar fashion before cell death events and would preferentially target S. aureus over E. coli or hRBC membranes.
Collapse
Affiliation(s)
- Marc-Antoine Sani
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Sónia Troeira Henriques
- the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Daniel Weber
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Frances Separovic
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| |
Collapse
|
25
|
Xu X, Lai R. The chemistry and biological activities of peptides from amphibian skin secretions. Chem Rev 2015; 115:1760-846. [PMID: 25594509 DOI: 10.1021/cr4006704] [Citation(s) in RCA: 220] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Xueqing Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology , Kunming 650223, Yunnan, China
| | | |
Collapse
|
26
|
Praporski S, Mechler A, Separovic F, Martin LL. Subtle Differences in Initial Membrane Interactions Underpin the Selectivity of Small Antimicrobial Peptides. Chempluschem 2014. [DOI: 10.1002/cplu.201402318] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Slavica Praporski
- School of Chemistry, Monash University, Clayton, VIC 3800 (Australia)
- Current address: Heart Research, Murdoch Childrens Research Institute, Parkville, VIC 3052 (Australia)
| | - Adam Mechler
- School of Chemistry, Monash University, Clayton, VIC 3800 (Australia)
- Current address: School of Molecular Sciences, La Trobe University, Bundoora, VIC 3086 (Australia)
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC 3010 (Australia)
| | | |
Collapse
|
27
|
Structural features of peptoid-peptide hybrids in lipid-water interfaces. FEBS Lett 2014; 588:3291-7. [DOI: 10.1016/j.febslet.2014.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/24/2014] [Accepted: 07/14/2014] [Indexed: 12/15/2022]
|
28
|
Dye-release assay for investigation of antimicrobial peptide activity in a competitive lipid environment. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:445-50. [PMID: 24906225 DOI: 10.1007/s00249-014-0970-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/13/2014] [Accepted: 05/20/2014] [Indexed: 10/25/2022]
Abstract
A dye-release method for investigating the effect of a competitive lipid environment on the activity of two membrane-disrupting antimicrobial peptides (AMP), maculatin 1.1 and aurein 1.2, is presented. The results support the general conclusion that AMP have greater affinity for negatively charged membranes, for example bacterial membranes, than for the neutral membrane surface found in eukaryotic cells, but only within a competitive lipid environment. Indeed, in a single-model membrane environment, both peptides were more potent against neutral vesicles than against charged vesicles. The approach was also used to investigate the effect of pre-incubating the peptides in a neutral lipid environment then introducing charged lipid vesicles. Maculatin was shown to migrate from the neutral lipid bilayers, where pores had already formed, to the charged membrane bilayers. This result was also observed for charged-to-charged bilayers but, interestingly, not for neutral-to-neutral lipid interfaces. Aurein was able to migrate from either lipid environment, indicating weaker binding to lipid membranes, and a different molecular mechanism for lysis of lipid bilayers. Competitive lipid environments could be used to assess other critical conditions that modulate the activity of membrane peptides or proteins.
Collapse
|
29
|
Siano A, Húmpola MV, de Oliveira E, Albericio F, Simonetta AC, Lajmanovich R, Tonarelli GG. Antimicrobial peptides from skin secretions of Hypsiboas pulchellus (Anura: Hylidae). JOURNAL OF NATURAL PRODUCTS 2014; 77:831-841. [PMID: 24717080 DOI: 10.1021/np4009317] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The skin of many amphibians produces a large repertoire of antimicrobial peptides that are crucial in the first line of defense against microbial invasion. Despite the immense richness of wild amphibians in Argentina, knowledge about peptides with antimicrobial properties is limited to a few species. Here we used LC-MS-MS to analyze samples of Hypsiboas pulchellus skin with the aim to identify antimicrobial peptides in the mass range of 1000 to 2000 Da. Twenty-three novel sequences were identified by MS, three of which were selected for chemical synthesis and further studies. The three synthetic peptides, named P1-Hp-1971, P2-Hp-1935, and P3-Hp-1891, inhibited the growth of two ATCC strains: Escherichia coli (MIC: 16, 33, and 17 μM, respectively) and Staphylococcus aureus (MIC: 8, 66, and 17 μM, respectively). P1-Hp-1971 and P3-Hp-1891 were the most active peptides. P1-Hp-1971, which showed the highest therapeutic indices (40 for E. coli and 80 for S. aureus), is a proline-glycine-rich peptide with a highly unordered structure, while P3-Hp-1891 adopts an amphipathic α-helical structure in the presence of 2,2,2-trifluoroethanol and anionic liposomes. This is the first peptidomic study of Hypsiboas pulchellus skin secretions to allow the identification of antimicrobial peptides.
Collapse
Affiliation(s)
- Alvaro Siano
- Departamento de Química Orgánica, Facultad de Bioquímica y Cs. Biológicas (FBCB), Universidad Nacional del Litoral (UNL) , Ciudad Universitaria, 3000, Santa Fe, Argentina
| | | | | | | | | | | | | |
Collapse
|
30
|
Perrin BS, Tian Y, Fu R, Grant CV, Chekmenev EY, Wieczorek W, Dao AE, Hayden RM, Burzynski CM, Venable RM, Sharma M, Opella SJ, Pastor RW, Cotten ML. High-resolution structures and orientations of antimicrobial peptides piscidin 1 and piscidin 3 in fluid bilayers reveal tilting, kinking, and bilayer immersion. J Am Chem Soc 2014; 136:3491-504. [PMID: 24410116 PMCID: PMC3985945 DOI: 10.1021/ja411119m] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Indexed: 01/16/2023]
Abstract
While antimicrobial peptides (AMPs) have been widely investigated as potential therapeutics, high-resolution structures obtained under biologically relevant conditions are lacking. Here, the high-resolution structures of the homologous 22-residue long AMPs piscidin 1 (p1) and piscidin 3 (p3) are determined in fluid-phase 3:1 phosphatidylcholine/phosphatidylglycerol (PC/PG) and 1:1 phosphatidylethanolamine/phosphatidylglycerol (PE/PG) bilayers to identify molecular features important for membrane destabilization in bacterial cell membrane mimics. Structural refinement of (1)H-(15)N dipolar couplings and (15)N chemical shifts measured by oriented sample solid-state NMR and all-atom molecular dynamics (MD) simulations provide structural and orientational information of high precision and accuracy about these interfacially bound α-helical peptides. The tilt of the helical axis, τ, is between 83° and 93° with respect to the bilayer normal for all systems and analysis methods. The average azimuthal rotation, ρ, is 235°, which results in burial of hydrophobic residues in the bilayer. The refined NMR and MD structures reveal a slight kink at G13 that delineates two helical segments characterized by a small difference in their τ angles (<10°) and significant difference in their ρ angles (~25°). Remarkably, the kink, at the end of a G(X)4G motif highly conserved among members of the piscidin family, allows p1 and p3 to adopt ρ angles that maximize their hydrophobic moments. Two structural features differentiate the more potent p1 from p3: p1 has a larger ρ angle and less N-terminal fraying. The peptides have comparable depths of insertion in PC/PG, but p3 is 1.2 Å more deeply inserted than p1 in PE/PG. In contrast to the ideal α-helical structures typically assumed in mechanistic models of AMPs, p1 and p3 adopt disrupted α-helical backbones that correct for differences in the amphipathicity of their N- and C-ends, and their centers of mass lie ~1.2-3.6 Å below the plane defined by the C2 atoms of the lipid acyl chains.
Collapse
Affiliation(s)
- B. Scott Perrin
- Laboratory
of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ye Tian
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093-0307, United States
| | - Riqiang Fu
- National High Magnetic
Field Laboratory, Tallahassee, Florida 32310, United
States
| | - Christopher V. Grant
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093-0307, United States
| | - Eduard Y. Chekmenev
- National High Magnetic
Field Laboratory, Tallahassee, Florida 32310, United
States
| | - William
E. Wieczorek
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Alexander E. Dao
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Robert M. Hayden
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Caitlin M. Burzynski
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Richard M. Venable
- Laboratory
of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Mukesh Sharma
- Department
of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Stanley J. Opella
- Department
of Chemistry and Biochemistry, University
of California San Diego, La Jolla, California 92093-0307, United States
| | - Richard W. Pastor
- Laboratory
of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Myriam L. Cotten
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| |
Collapse
|
31
|
Bobone S, Bocchinfuso G, Park Y, Palleschi A, Hahm KS, Stella L. The importance of being kinked: role of Pro residues in the selectivity of the helical antimicrobial peptide P5. J Pept Sci 2013; 19:758-69. [DOI: 10.1002/psc.2574] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/17/2013] [Accepted: 09/20/2013] [Indexed: 01/17/2023]
Affiliation(s)
- Sara Bobone
- Dipartimento di Scienze e Tecnologie Chimiche; Università di Roma Tor Vergata; Via della Ricerca Scientifica 1 00133 Rome Italy
| | - Gianfranco Bocchinfuso
- Dipartimento di Scienze e Tecnologie Chimiche; Università di Roma Tor Vergata; Via della Ricerca Scientifica 1 00133 Rome Italy
| | - Yoonkyung Park
- Department of Cellular & Molecular Medicine, School of Medicine; Chosun University; Gwangju 501-759 Korea
| | - Antonio Palleschi
- Department of Cellular & Molecular Medicine, School of Medicine; Chosun University; Gwangju 501-759 Korea
| | - Kyung-Soo Hahm
- BioLeaders Corp.; 559 Yongsan-Dong, Yuseong-Ku Daejeon 305-500 Korea
| | - Lorenzo Stella
- Dipartimento di Scienze e Tecnologie Chimiche; Università di Roma Tor Vergata; Via della Ricerca Scientifica 1 00133 Rome Italy
| |
Collapse
|
32
|
Maculatin 1.1 disrupts Staphylococcus aureus lipid membranes via a pore mechanism. Antimicrob Agents Chemother 2013; 57:3593-600. [PMID: 23689707 DOI: 10.1128/aac.00195-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Maculatin 1.1 (Mac1) showed potent activity against Staphylococcus aureus with an MIC of 7 μM. The mode of action of Mac1 was investigated by combining assays with S. aureus cells and lipid vesicles mimicking their membrane composition. A change in Mac1 conformation was monitored by circular dichroism from random coil to ca. 70% α-helix structure in contact with vesicles. Electron micrographs of S. aureus incubated with Mac1 showed rough and rippled cell surfaces. An uptake of 65% of small (FD, 4 kDa [FD-4]) and 35% of large (RD, 40 kDa [RD-40]) fluorescent dextrans by S. aureus was observed by flow cytometry and indicate that Mac1 formed a pore of finite size. In model membranes with both dyes encapsulated together, the full release of FD-4 occurred, but only 40% of RD-40 was reached, supporting the flow cytometry results, and indicating a pore size between 1.4 and 4.5 nm. Finally, solid-state nuclear magnetic resonance showed formation of an isotropic phase signifying highly mobile lipids such as encountered in a toroidal pore structure. Overall, Mac1 is a promising antimicrobial peptide with the potent capacity to form pores in S. aureus membranes.
Collapse
|
33
|
Fernandez D, Lee TH, Sani MA, Aguilar MI, Separovic F. Proline facilitates membrane insertion of the antimicrobial peptide maculatin 1.1 via surface indentation and subsequent lipid disordering. Biophys J 2013; 104:1495-507. [PMID: 23561526 PMCID: PMC3617439 DOI: 10.1016/j.bpj.2013.01.059] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/23/2013] [Accepted: 01/28/2013] [Indexed: 01/08/2023] Open
Abstract
The role of proline in the disruption of membrane bilayer structure upon antimicrobial peptide (AMP) binding was studied. Specifically, (31)P and (2)H solid-state NMR and dual polarization interferometry (DPI) were used to analyze the membrane interactions of three AMPs: maculatin 1.1 and two analogs in which Pro-15 is replaced by Gly and Ala. For NMR, deuterated dimyristoylphosphatidylcholine (d54-DMPC) and d54-DMPC/dimyristoylphosphatidylglycerol (DMPG) were used to mimic eukaryotic and prokaryotic membranes, respectively. In fluid-phase DMPC bilayer systems, the peptides interacted primarily with the bilayer surface, with the native peptide having the strongest interaction. In the mixed DMPC/DMPG bilayers, maculatin 1.1 induced DMPG phase separation, whereas the analogs promoted the formation of isotropic and lipid-enriched phases with an enhanced effect relative to the neutral DMPC bilayers. In gel-phase DMPC vesicles, the native peptide disrupted the bilayer via a surface mechanism, and the effect of the analogs was similar to that observed in the fluid phase. Real-time changes in bilayer order were examined via DPI, with changes in bilayer birefringence analyzed as a function of the peptide mass bound to the bilayer. Although all three peptides decreased the bilayer order as a function of bound concentration, maculatin 1.1 caused the largest change in bilayer structure. The NMR data indicate that maculatin 1.1 binds predominantly at the surface regions of the bilayer, and both NMR and DPI results indicate that this binding leads to a drop in bilayer order. Overall, the results demonstrate that the proline at residue 15 plays a central role in the membrane interaction of maculatin 1.1 by inducing a significant change in membrane order and affecting the ability of the bilayer to recover from structural changes induced by the binding and insertion of the peptide.
Collapse
Affiliation(s)
- David I. Fernandez
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria, Australia
| |
Collapse
|
34
|
Parton DL, Akhmatskaya EV, Sansom MSP. Multiscale simulations of the antimicrobial peptide maculatin 1.1: water permeation through disordered aggregates. J Phys Chem B 2012; 116:8485-93. [PMID: 22380536 DOI: 10.1021/jp212358y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The antimicrobial peptide maculatin 1.1 (M1.1) is an amphipathic α-helix that permeabilizes lipid bilayers. In coarse-grained molecular dynamics (CG MD) simulations, M1.1 has previously been shown to form membrane-spanning aggregates in DPPC bilayers. In this study, a simple multiscale methodology has been applied to allow sampling of important regions of the free energy surface at higher resolution. Thus, by back-converting the CG configurations to atomistic representations, it is shown that water is able to permeate through the M1.1 aggregates. Investigation of aggregate stoichiometry shows that at least six peptides are required for water permeation. The aggregates are dynamically disordered structures, and water flux occurs through irregular, fluctuating channels. The results are discussed in relation to experimental data and other simulations of antimicrobial peptides.
Collapse
Affiliation(s)
- Daniel L Parton
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | | | | |
Collapse
|
35
|
Structural effects of the antimicrobial peptide maculatin 1.1 on supported lipid bilayers. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:47-59. [DOI: 10.1007/s00249-012-0796-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/25/2012] [Accepted: 02/02/2012] [Indexed: 01/23/2023]
|
36
|
The Simian virus 40 late viral protein VP4 disrupts the nuclear envelope for viral release. J Virol 2012; 86:3180-92. [PMID: 22238309 DOI: 10.1128/jvi.07047-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Simian virus 40 (SV40) appears to initiate cell lysis by expressing the late viral protein VP4 at the end of infection to aid in virus dissemination. To investigate the contribution of VP4 to cell lysis, VP4 was expressed in mammalian cells where it was predominantly observed along the nuclear periphery. The integrity of the nuclear envelope was compromised in these cells, resulting in the mislocalization of a soluble nuclear marker. Using assays that involved the cellular expression of VP4 or the treatment of cells with purified VP4, we found that the central hydrophobic domain and a proximal C-terminal nuclear localization signal of VP4 were required for (i) cytolysis associated with prolonged expression; (ii) nuclear envelope accumulation; and (iii) disruption of the nuclear, red blood cell, or host cell membranes. Furthermore, a conserved proline within the hydrophobic domain was required for membrane perforation, suggesting that this residue was crucial for VP4 cytolytic activity. These results indicate that VP4 forms pores in the nuclear membrane leading to lysis and virus release.
Collapse
|
37
|
Harris F, Dennison SR, Singh J, Phoenix DA. On the selectivity and efficacy of defense peptides with respect to cancer cells. Med Res Rev 2011; 33:190-234. [PMID: 21922503 DOI: 10.1002/med.20252] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Here, we review potential determinants of the anticancer efficacy of innate immune peptides (ACPs) for cancer cells. These determinants include membrane-based factors, such as receptors, phosphatidylserine, sialic acid residues, and sulfated glycans, and peptide-based factors, such as residue composition, sequence length, net charge, hydrophobic arc size, hydrophobicity, and amphiphilicity. Each of these factors may contribute to the anticancer action of ACPs, but no single factor(s) makes an overriding contribution to their overall selectivity and toxicity. Differences between the anticancer actions of ACPs seem to relate to different levels of interplay between these peptide and membrane-based factors.
Collapse
Affiliation(s)
- Frederick Harris
- School of Forensic and Investigative Sciences, University of Central Lancashire, Preston, Lancashire, United Kingdom
| | | | | | | |
Collapse
|
38
|
Chia CSB, Gong Y, Bowie JH, Zuegg J, Cooper MA. Membrane binding and perturbation studies of the antimicrobial peptides caerin, citropin, and maculatin. Biopolymers 2011; 96:147-57. [PMID: 20564028 DOI: 10.1002/bip.21438] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Citropin 1.1, maculatin 1.1, and caerin 1.1 are short antibacterial cationic peptides from the skin glands of the Australian tree frog Litoria species. Several analogues have been synthesized to give a better insight into the relationship between the structure of the peptides and their antibacterial and haemolytic activity. Binding studies using a surface plasmon resonance (SPR) biosensor together with a vesicle-capture sensor chip have been used to investigate selectivity of the peptides and their analogues for 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles, as well as for vesicles made from lipid extracts from Escherichia coli and bovine brain. Data obtained for membrane selectivity using natural lipid extracts show better correlation with minimum inhibitory concentration (MIC) values against Gram-positive bacteria and haemolytic activity than that obtained using synthetic DMPG and DMPC. Electron microscopy and membrane leakage studies using Gram-positive bacteria gave further insight into the membrane disruption properties of the peptides. For maculatin 1.1, it was found that the central proline residue, which is responsible for a bend in the alpha-helical structure, is essential not only for the antibacterial activity but also for binding, and perturbation of membranes. The caerin analogues showed only small variations in their MIC values and membrane binding. In contrast, for citropin 1.1, the analogue replacing the aspartate with a lysine showed the lowest MIC against Gram-positive bacteria and best membrane binding to E. coli lipid extracts, coinciding with an increased hydrophobic moment of the peptide. These data give further insight into these antimicrobial natural products, toward the development and evaluation of these and other analogues as potential antibiotics.
Collapse
Affiliation(s)
- C S Brian Chia
- Experimental Therapeutics Centre, Agency for Science, Technology and Research, 31 Biopolis Way, #03-01 Nanos, 138669, Singapore
| | | | | | | | | |
Collapse
|
39
|
Wang T, Andreazza HJ, Pukala TL, Sherman PJ, Calabrese AN, Bowie JH. Histidine-containing host-defence skin peptides of anurans bind Cu2+. An electrospray ionisation mass spectrometry and computational modelling study. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:1209-1221. [PMID: 21488120 DOI: 10.1002/rcm.4981] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Anuran peptides which contain His, including caerin 1.8 (GLFKVLGSVAKHLLPHVVPVIAEKL-NH(2)), caerin 1.2 (GLLGVLGSVAKHVLPHVVPVIAEHL-NH(2)), Ala(15) maculatin 1.1 (GLFGVLAKVAAHVVAIEHF-NH(2)), fallaxidin 4.1 (GLLSFLPKVIGHLIHPPS-OH), riparin 5.1 (IVSYPDDAGEHAHKMG-NH(2)) and signiferin 2.1 (IIGHLIKTALGMLGL-NH(2)), all form MMet(2+) and (M + Met(2+)-2H(+))(2+) cluster ions (where Met is Cu, Mg and Zn) following electrospray ionisation (ESI) in a Waters QTOF 2 mass spectrometer. Peaks due to Cu(II) complexes are always the most abundant relative to other metal complexes. Information concerning metal(2+) connectivity in a complex has been obtained (at least in part) using b and y fragmentation data from ESI collision-induced dissociation tandem mass spectrometry (CID MS/MS). Theoretical calculations, using AMBER version 10, show that MCu(2+) complexes with the membrane active caerin 1.8, Ala(15) maculatin 1.1 and fallaxidin 4.1 are four-coordinate and approximating square planar, with ligands including His and Lys, together with the carbonyl oxygens of particular backbone amide groups. When binding can occur through two His, or one His and one Lys, the His/Lys ligand structure is the more stable for the studied systems. The three-dimensional (3D) structures of the complexes are always different from the previously determined structures of the uncomplexed model peptides (using 2D nuclear magnetic resonance (NMR) spectroscopy in membrane-mimicking solvents like trifluoroethanol/water).
Collapse
Affiliation(s)
- Tianfang Wang
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia, Australia
| | | | | | | | | | | |
Collapse
|
40
|
Xie Y, Fleming E, Chen JL, Elmore DE. Effect of proline position on the antimicrobial mechanism of buforin II. Peptides 2011; 32:677-82. [PMID: 21277926 PMCID: PMC3060972 DOI: 10.1016/j.peptides.2011.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/14/2011] [Accepted: 01/14/2011] [Indexed: 01/03/2023]
Abstract
Buforin II (BF2) is a histone-derived antimicrobial peptide that causes cell death by translocating across membranes and interacting with nucleic acids. It contains one proline residue critical for its function. Previous research found that mutations replacing proline lead to decreased membrane translocation and antimicrobial activity as well as increased membrane permeabilization. This study further investigates the role of proline in BF2's antimicrobial mechanism by considering the effect of changing proline position on membrane translocation, membrane permeabilization, and antimicrobial activity. For this purpose, four mutants were made with proline substitution (P11A) or relocation (P11A/G7P, P11A/V12P, P11A/V15P). These mutations altered the amount of helical content. Although antimicrobial activity correlated with the α-helical content for the peptides containing proline, membrane translocation did not. This observation suggests that factors in BF2's bactericidal mechanism other than translocation must be altered by these mutations. To better explain these trends we also measured the nucleic acid binding and membrane permeabilization of the mutant peptides. A comparison of mutant and wild type BF2 activity revealed that BF2 relies principally on membrane translocation and nucleic acid binding for antimicrobial activity, although membrane permeabilization may play a secondary role for some BF2 variants. A better understanding of the role of proline in the BF2 antimicrobial mechanism will contribute to the further design and development of BF2 analogs. Moreover, since proline residues are prevalent among other antimicrobial peptides, this systematic characterization of BF2 provides general insights that can promote our understanding of other systems.
Collapse
Affiliation(s)
- Yang Xie
- Department of Chemistry; Wellesley College; 106 Central St.; Wellesley, MA 02481
| | - Eleanor Fleming
- Department of Chemistry; Wellesley College; 106 Central St.; Wellesley, MA 02481
| | - Jessica L. Chen
- Department of Chemistry; Wellesley College; 106 Central St.; Wellesley, MA 02481
| | - Donald E. Elmore
- Department of Chemistry; Wellesley College; 106 Central St.; Wellesley, MA 02481
| |
Collapse
|
41
|
Abstract
AbstractIncreased prevalence of multi-drug resistance in pathogens has encouraged researchers to focus on finding novel forms of anti-infective agents. Antimicrobial peptides (AMPs) found in animal secretions are components of host innate immune response and have survived eons of pathogen evolution. Thus, they are likely to be active against pathogens and even those that are resistant to conventional drugs. Many peptides have been isolated and shown to be effective against multi-drug resistant pathogens. More than 500 AMPs have been identified from amphibians. The abundance of AMPs in frog skin is remarkable and constitutes a rich source for design of novel pharmaceutical molecules. Expression and post-translational modifications, discovery, activities and probable therapeutic application prospects of amphibian AMPs will be discussed in this article.
Collapse
Affiliation(s)
- Yao Xiao
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - Cunbao Liu
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| | - Ren Lai
- 1Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China
| |
Collapse
|
42
|
Chen R, Mark AE. The effect of membrane curvature on the conformation of antimicrobial peptides: implications for binding and the mechanism of action. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2011; 40:545-53. [PMID: 21267557 PMCID: PMC3070085 DOI: 10.1007/s00249-011-0677-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 12/06/2010] [Accepted: 01/11/2011] [Indexed: 01/20/2023]
Abstract
Short cationic antimicrobial peptides (AMPs) are believed to act either by inducing transmembrane pores or disrupting membranes in a detergent-like manner. For example, the antimicrobial peptides aurein 1.2, citropin 1.1, maculatin 1.1 and caerin 1.1, despite being closely related, appear to act by fundamentally different mechanisms depending on their length. Using molecular dynamics simulations, the structural properties of these four peptides have been examined in solution as well as in a variety of membrane environments. It is shown that each of the peptides has a strong preference for binding to regions of high membrane curvature and that the structure of the peptides is dependent on the degree of local curvature. This suggests that the shorter peptides aurein 1.2 and citropin 1.1 act via a detergent-like mechanism because they can induce high local, but not long-range curvature, whereas the longer peptides maculatin 1.1 and caerin 1.1 require longer range curvature to fold and thus bind to and stabilize transmembrane pores.
Collapse
Affiliation(s)
- Rong Chen
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| |
Collapse
|
43
|
Fernandez DI, Sani MA, Separovic F. Interactions of the Antimicrobial Peptide Maculatin 1.1 and Analogues with Phospholipid Bilayers. Aust J Chem 2011. [DOI: 10.1071/ch11062] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The interactions of the antimicrobial peptide, maculatin 1.1 (GLFGVLAKVAAHVVPAIAEHF-NH2) and two analogues, with model phospholipid membranes have been studied using solid-state NMR and circular dichroism spectroscopy. Maculatin 1.1 and the P15G and P15A analogues displayed minimal secondary structure in water, but with zwitterionic dimyristoylphosphatidylcholine (DMPC) vesicles displayed a significant increase in α-helical content. In mixed phospholipid vesicles of DMPC and anionic dimyristoylphosphatidylglycerol (DMPG), each peptide was highly structured with ~80% α-helical content. In DMPC vesicles, the native peptide displayed moderate head group interaction and significant perturbation of the lipid acyl chains. In DMPC/DMPG vesicles, maculatin 1.1 promoted formation of a DMPG-enriched phase and moderately increased disorder towards acyl chain ends of DMPC in the mixed bilayer. Both analogues showed reduced phospholipid head group interactions with DMPC but displayed significant interactions with the mixed lipid system. These effects support the preferential activity of these antimicrobial peptides for bacterial membranes.
Collapse
|
44
|
Galloux M, Libersou S, Alves ID, Marquant R, Salgado GF, Rezaei H, Lepault J, Delmas B, Bouaziz S, Morellet N. NMR structure of a viral peptide inserted in artificial membranes: a view on the early steps of the birnavirus entry process. J Biol Chem 2010; 285:19409-21. [PMID: 20385550 PMCID: PMC2885221 DOI: 10.1074/jbc.m109.076083] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 03/08/2010] [Indexed: 11/06/2022] Open
Abstract
Nonenveloped virus must penetrate the cellular membrane to access the cytoplasm without the benefit of membrane fusion. For birnavirus, one of the peptides present in the virus capsid, pep46 for infectious bursal disease virus, is able to induce pores into membranes as an intermediate step of the birnavirus-penetration pathway. Using osmotic protection experiments, we demonstrate here that pep46 and its pore-forming N-terminal moiety (pep22) form pores of different diameters, 5-8 and 2-4 nm, respectively, showing that both pep46 moieties participate to pore formation. The solution structures of pep46, pep22, and pep24 (the pep46 C-terminal moiety) in different hydrophobic environments and micelles determined by (1)H NMR studies provide structural insights of the pep46 domain interaction. In CDCl(3)/CD(3)OH mixture and in dodecylphosphocholine micelles, the N-terminal domain of pep46 is structured in a long kinked helix, although the C terminus is structured in one or two helices depending upon the solvents used. We also show that the folding and the proline isomerization status of pep46 depend on the type of hydrophobic environment. NMR spectroscopy with labeled phospholipid micelles, differential scanning calorimetry, and plasmon waveguide resonance studies show the peptides lie parallel to the lipid-water interface, perturbing the fatty acid chain packing. All these data lead to a model in which the two domains of pep46 interact with the membrane to form pores.
Collapse
Affiliation(s)
- Marie Galloux
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Sonia Libersou
- the CNRS UMR 2472, INRA 1157, Virologie Moléculaire et Structurale, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
| | - Isabel D. Alves
- the UPMC Paris 06, CNRS, UMR 7203, Laboratoire des BioMolécules, FR 2769, Case Courier 182, 4 Place Jussieu, 75252 Paris Cedex 05, and
| | - Rodrigue Marquant
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
| | - Gilmar F. Salgado
- the UPMC Paris 06, CNRS, UMR 7203, Laboratoire des BioMolécules, FR 2769, Case Courier 182, 4 Place Jussieu, 75252 Paris Cedex 05, and
| | - Human Rezaei
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Jean Lepault
- the CNRS UMR 2472, INRA 1157, Virologie Moléculaire et Structurale, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
| | - Bernard Delmas
- the Unité de Virologie et Immunologie Moléculaires, UR892, Bâtiment de Biotechnologies, INRA, Domaine de Vilvert, F-78350 Jouy-en-Josas
| | - Serge Bouaziz
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
| | - Nelly Morellet
- From the Unité de Pharmacologie Chimique et Génétique, CNRS, UMR 8151, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 4 Avenue de l'Observatoire, Paris, F-75270 Cedex 06
| |
Collapse
|
45
|
Luo J, Parsons SM. Conformational Propensities of Peptides Mimicking Transmembrane Helix 5 and Motif C in Wild-type and Mutant Vesicular Acetylcholine Transporters. ACS Chem Neurosci 2010; 1:381-390. [PMID: 20544010 PMCID: PMC2882315 DOI: 10.1021/cn900033s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 01/21/2010] [Indexed: 11/29/2022] Open
Abstract
Vesicular acetylcholine transporter (VAChT) is a member of the major facilitator superfamily (MFS). It contains conserved sequence motifs originally defined in the bacterial multidrug resistance transporter family of the MFS. Motif C (GSLV(227) A(228)PPFGGIL) is located at the C-terminal end of transmembrane helix 5 (TM 5) in VAChT. The motif is rich in glycine and proline residues that often have special roles in backbone conformations of TMs. The A228G mutant of VAChT transports > 3-fold faster than wild type does [Chandrasekaran et al. (2006)J. Neurochem. 98, 1551-1559.]. In the current study, the structure of Loop 4/5, TM 5, and Motif C were taken from a three-dimensional homology model for human VAChT. The peptide was immersed in implicit membrane, energy minimized, and molecular dynamics (MD) were simulated. Kinking and wobbling occur in otherwise helical peptide at the hinge residues L226 and V227. MD also were simulated for A228G single-mutant and V227L-A228A double-mutant peptides to investigate the structural roles of the A228G mutation and beta-branching at V227. Mutant peptides exhibit increased wobbling at the hinge residues, but in the double mutant the increase is less. Because Motif C participates in the interface that mediates hypothesized rocker-switch re-orientation of the acetylcholine binding site during transport, dynamics in Motif C might be an important contributor to transport rate.
Collapse
Affiliation(s)
- Jia Luo
- Department of Chemistry and Biochemistry, Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9510
| | - Stanley M. Parsons
- Department of Chemistry and Biochemistry, Neuroscience Research Institute, University of California, Santa Barbara, California 93106-9510
| |
Collapse
|
46
|
Conformational and dynamics simulation study of antimicrobial peptide hedistin-heterogeneity of its helix-turn-helix motif. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2497-508. [PMID: 19819221 DOI: 10.1016/j.bbamem.2009.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 09/27/2009] [Accepted: 10/02/2009] [Indexed: 11/23/2022]
Abstract
Hedistin is an antimicrobial peptide isolated from the coelomocytes of Nereis diversicolor, possessing activity against a large spectrum of bacteria including the methicillin resistant Staphylococcus aureus and Vibrio alginolyticus. The three-dimensional structure of hedistin in both aqueous solution and deuterated dodecylphosphocholine (DPC) micelles was examined using circular dichroism (CD) and nuclear magnetic resonance (NMR) techniques. And, the early events of the antibacterial process of hedistin were simulated using palmitoyl-oleoyl-phophatidylcholine (POPC) lipid bilayers and molecular dynamics (MD) simulation methods. Hedistin lacks secondary structure in aqueous solution, however, in DPC micelles, it features with a heterogeneous helix-turn-helix moiety and exhibits obvious amphipathic nature. The turn region (residues Val9-Thr12) in the moiety is a four-residue hinge, lying in between the first N-terminal alpha-helix (residues Leu5-Lys8) and the second alpha-helix (residues Val13-Ala17) regions and causing an approximately 120 degrees angle between the axes of the two helices. The segmental and nonlinear nature of hedistin structure is referred to as the heterogeneity of its helix-turn-helix motif which was found to be corresponding to a kind of discrete dynamics behavior, herein coined as its dynamical heterogeneity, at the early stage (0-50 ns) of the MD simulations. That is, the first helix segment, prior to (at 310 K) or following (at 363 K) the second helix, binds to the lipid head-group region and subsequently permeates into the hydrophobic lipid tail region, and the hinge is the last portion entering the lipid environment. This result implies that hedistin may adopt a "carpet" model action when disrupting bacterial membrane.
Collapse
|
47
|
van Dijk A, Molhoek EM, Veldhuizen EJ, Bokhoven JLTV, Wagendorp E, Bikker F, Haagsman HP. Identification of chicken cathelicidin-2 core elements involved in antibacterial and immunomodulatory activities. Mol Immunol 2009; 46:2465-73. [DOI: 10.1016/j.molimm.2009.05.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 05/18/2009] [Indexed: 11/28/2022]
|
48
|
Sikorska E, Greber K, Rodziewicz-Motowidło S, Szultka L, Lukasiak J, Kamysz W. Synthesis and antimicrobial activity of truncated fragments and analogs of citropin 1.1: The solution structure of the SDS micelle-bound citropin-like peptides. J Struct Biol 2009; 168:250-8. [PMID: 19616100 DOI: 10.1016/j.jsb.2009.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 07/11/2009] [Accepted: 07/14/2009] [Indexed: 01/13/2023]
Abstract
Citropin 1.1 is a basic, highly hydrophobic, 16-amino acid peptide (GLFDVIKKVASVIGGL-NH(2)), displaying wide-spectrum antimicrobial activities. In this paper we describe the synthesis and antimicrobial properties of citropin 1.1 and its 18 analogs constituting mostly truncated fragments of citropin 1.1. Moreover, we examined conformational properties of citropin 1.1 and its two analogs, (1-12)citropin and (1-13)[Ala(4)]citropin, using FTIR, CD and NMR spectroscopies. Three-dimensional structures of the peptides were determined using molecular dynamics (MD) simulations with time-averaged (TAV) restraints obtained from NMR spectra measured in micellar concentration of sodium dodecyl sulfate (SDS). Earlier investigations showed that in TFE solution, citropin 1.1 is a single helix all along the backbone. However, this structure is not retained in the presence of SDS micelle. In H(2)O/SDS-d(25) solution, citropin 1.1 adopts two alpha-helices in the fragments 4-7 and 10-16, respectively, separated by betaIV-turn at position 8, 9. The (1-12)citropin adopts an alpha-helical structure along the entire backbone. In turn, (1-13)[Ala(4)]citropin demonstrates the tendency to adopt only a short alpha-helix in the middle part. Moreover, the conversion of alpha-helix to 3(10)-helix has been noticed in about 30% of conformations. The 3(10)-helical units could be thermodynamic intermediates during folding and unfolding of the alpha-helical segment of the peptide.
Collapse
|
49
|
Haney EF, Hunter HN, Matsuzaki K, Vogel HJ. Solution NMR studies of amphibian antimicrobial peptides: linking structure to function? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1639-55. [PMID: 19272309 DOI: 10.1016/j.bbamem.2009.01.002] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 12/19/2008] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
Abstract
The high-resolution three-dimensional structure of an antimicrobial peptide has implications for the mechanism of its antimicrobial activity, as the conformation of the peptide provides insights into the intermolecular interactions that govern the binding to its biological target. For many cationic antimicrobial peptides the negatively charged membranes surrounding the bacterial cell appear to be a main target. In contrast to what has been found for other classes of antimicrobial peptides, solution NMR studies have revealed that in spite of the wide diversity in the amino acid sequences of amphibian antimicrobial peptides (AAMPs), they all adopt amphipathic alpha-helical structures in the presence of membrane-mimetic micelles, bicelles or organic solvent mixtures. In some cases the amphipathic AAMP structures are directly membrane-perturbing (e.g. magainin, aurein and the rana-box peptides), in other instances the peptide spontaneously passes through the membrane and acts on intracellular targets (e.g. buforin). Armed with a high-resolution structure, it is possible to relate the peptide structure to other relevant biophysical and biological data to elucidate a mechanism of action. While many linear AAMPs have significant antimicrobial activity of their own, mixtures of peptides sometimes have vastly improved antibiotic effects. Thus, synergy among antimicrobial peptides is an avenue of research that has recently attracted considerable attention. While synergistic relationships between AAMPs are well described, it is becoming increasingly evident that analyzing the intermolecular interactions between these peptides will be essential for understanding the increased antimicrobial effect. NMR structure determination of hybrid peptides composed of known antimicrobial peptides can shed light on these intricate synergistic relationships. In this work, we present the first NMR solution structure of a hybrid peptide composed of magainin 2 and PGLa bound to SDS and DPC micelles. The hybrid peptide adopts a largely helical conformation and some information regarding the inter-helix organization of this molecule is reported. The solution structure of the micelle associated MG2-PGLa hybrid peptide highlights the importance of examining structural contributions to the synergistic relationships but it also demonstrates the limitations in the resolution of the currently used solution NMR techniques for probing such interactions. Future studies of antimicrobial peptide synergy will likely require stable isotope-labeling strategies, similar to those used in NMR studies of proteins.
Collapse
Affiliation(s)
- Evan F Haney
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | | | | | | |
Collapse
|
50
|
Bilusich D, Bowie JH. Fragmentations of (M-H)- anions of underivatised peptides. Part 2: Characteristic cleavages of Ser and Cys and of disulfides and other post-translational modifications, together with some unusual internal processes. MASS SPECTROMETRY REVIEWS 2009; 28:20-34. [PMID: 18989895 DOI: 10.1002/mas.20206] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In a previous review (Bowie, Brinkworth, & Dua (2002); Mass Spectrom Rev 21:87-107) we described the characteristic backbone cleavages and side chain fragmentations which occur from (M-H)(-) parent anions of underivatized peptides. This work is briefly summarized in the present review. Cys was not described in the previous review: here we describe the Cys characteristic side chain loss of H(2)S, together with its gamma backbone cleavage. These processes are compared with those of the related Ser. All experimental observations are backed up with theoretical studies at the HF/6-31G(d)//AM1 level of theory, a level of theory which we have shown gives good geometries and acceptable relative energies. The negative ion cleavages of a number of post-translational modifications are described. Negative ion mass spectrometry is the method of choice for identification of disulfides in both peptides and proteins. Intramolecular disulfides are identified by the presence of the fragment anion [(M-H)(-)-H(2)S(2)], and CID MS2 of this fragment normally identifies the positions of the two Cys residues and often the full sequence of the peptide. An unsymmetrically substituted intermolecular disulfide can give up to eight characteristic fragment anions, and CID MS2 of some, or all of these often provides the full sequence of those peptides which form the initial intermolecular disulfide linkage. Negative ion cleavages of disulfides are the most energetically favored of all peptide negative cleavages studied to date. Negative ion mass spectrometry is also valuable for the identification of pyroglutamates, sulfates and phosphates. Finally, some unusual fragmentations are described which involve cyclization/elimination reactions which require the decomposing (M-H)(-) parent anions to adopt the same helical conformation that these peptides have in solution.
Collapse
Affiliation(s)
- Daniel Bilusich
- Department of Chemistry, The University of Adelaide, SA 5005, Australia
| | | |
Collapse
|