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Deciphering Structure-Function Relationship Unveils Salt-Resistant Mode of Action of a Potent MRSA-Inhibiting Antimicrobial Peptide, RR14. J Bacteriol 2022; 204:e0031222. [PMID: 36377870 PMCID: PMC9765028 DOI: 10.1128/jb.00312-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Multidrug-resistant (MDR) bacteria lead to considerable morbidity and mortality, threatening public health worldwide. In particular, infections of methicillin-resistant Staphylococcus aureus (MRSA) in hospital and community settings are becoming a serious health problem. Antimicrobial peptides (AMPs) are considered novel therapeutic targets against MDR bacteria. However, salt sensitivity reduces the bactericidal potency of AMPs, posing a major obstacle for their development as antibiotics. Thus, the design and development of salt-insensitive peptides with potent antibacterial activity is imperative. Here, we employed biochemical and biophysical examinations coupled with molecular modeling to systematically investigate the structure-function relationship of a novel salt-insensitive AMP, RR14. The secondary structure of RR14 was characterized as an apparent α-helix, a structure that confers strong membrane-permeabilizing ability targeting bacterial-mimetic membranes. Additionally, the bioactive structure of RR14 was determined in complex with dodecylphosphocholine (DPC) micelles, where it possesses a central α-helical segment comprising residues R4 to K13 (R4-K13). RR14 was observed to orient itself into the DPC micelle with its N terminus and the α-helical segment (I5-R10) buried inside the micelles, which is essential for membrane permeabilization and bactericidal activity. Moreover, the specific and featured arrangement of positively charged residues of RR14 on its amphipathic helical conformation has great potential to render its strong salt resistance ability. Our study explored the structure-function relationship of RR14, explaining its possible mode of action against MRSA and other microbes. The insights obtained are of great applicability for the development of new antibacterial agents. IMPORTANCE Many antimicrobial peptides have been observed to become inactive in the presence of high salt concentrations. To further develop new and novel AMPs with potent bactericidal activity and salt insensitivity, understanding the structural basis for salt resistance is important. Here, we employed biochemical and biophysical examinations to systematically investigate the structure-function relationship of a novel salt-insensitive AMP, RR14. RR14 was observed to orient itself into DPC micelles with the N terminus and the α-helical segment (I5-R10) buried inside the micelles, which is essential for membrane permeabilization and bactericidal activity. Moreover, the specific and featured arrangement of cationic residues of RR14 on its amphipathic helical conformation renders its strong salt resistance ability. The insights obtained are of great applicability for developing new antibacterial agents.
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Pinheiro-Aguiar R, do Amaral VSG, Pereira IB, Kurtenbach E, Almeida FCL. Nuclear magnetic resonance solution structure of Pisum sativum defensin 2 provides evidence for the presence of hydrophobic surface-clusters. Proteins 2020; 88:242-246. [PMID: 31294889 DOI: 10.1002/prot.25783] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/26/2019] [Accepted: 07/06/2019] [Indexed: 11/12/2022]
Abstract
Pisum sativum defensin 2 (Psd2) is a small (4.7 kDa) antifungal peptide whose structure is held together by four conserved disulfide bridges. Psd2 shares the cysteine-stabilized alpha-beta (CSαβ) fold, which lacks a regular hydrophobic core. All hydrophobic residues are exposed to the surface, except for leucine 6. They are clustered in the surface formed by two loops, between β1 and α-helix and β2 and β3 sheets. The observation of surface hydrophobic clusters reveals a remarkable evolution of the CSαβ fold to expose and reorganize hydrophobic residues, which facilitates creating versatile binding sites.
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Affiliation(s)
- Ramon Pinheiro-Aguiar
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Virginia S G do Amaral
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Iuri B Pereira
- Campus Macaé Professor Aloísio Teixeira, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Eleonora Kurtenbach
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Fabio C L Almeida
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
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de Paula VS, Valente AP. A Dynamic Overview of Antimicrobial Peptides and Their Complexes. Molecules 2018; 23:molecules23082040. [PMID: 30111717 PMCID: PMC6222744 DOI: 10.3390/molecules23082040] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/05/2018] [Accepted: 08/09/2018] [Indexed: 01/06/2023] Open
Abstract
In this narrative review, we comprehensively review the available information about the recognition, structure, and dynamics of antimicrobial peptides (AMPs). Their complex behaviors occur across a wide range of time scales and have been challenging to portray. Recent advances in nuclear magnetic resonance and molecular dynamics simulations have revealed the importance of the molecular plasticity of AMPs and their abilities to recognize targets. We also highlight experimental data obtained using nuclear magnetic resonance methodologies, showing that conformational selection is a major mechanism of target interaction in AMP families.
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Affiliation(s)
- Viviane Silva de Paula
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA.
| | - Ana Paula Valente
- Centro de Biologia Estrutural e Bioimagem, Instituto de Bioquímica Médica, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.
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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.
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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.
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Structural and Dynamic Insights of the Interaction between Tritrpticin and Micelles: An NMR Study. Biophys J 2017; 111:2676-2688. [PMID: 28002744 DOI: 10.1016/j.bpj.2016.10.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/14/2016] [Accepted: 10/27/2016] [Indexed: 01/02/2023] Open
Abstract
A large number of antimicrobial peptides (AMPs) acts with high selectivity and specificity through interactions with membrane lipid components. These peptides undergo complex conformational changes in solution; upon binding to an interface, one major conformation is stabilized. Here we describe a study of the interaction between tritrpticin (TRP3), a cathelicidin AMP, and micelles of different chemical composition. The peptide's structure and dynamics were examined using one-dimensional and two-dimensional NMR. Our data showed that the interaction occurred by conformational selection and the peptide acquired similar structures in all systems studied, despite differences in detergent headgroup charge or dipole orientation. Fluorescence and paramagnetic relaxation enhancement experiments showed that the peptide is located in the interface region and is slightly more deeply inserted in 1-myristoyl-2-hydroxy-sn-glycero-3-phospho-1'-rac-glycerol (LMPG, anionic) than in 1-lauroyl-2-hydroxy-sn-glycero-3-phosphocholine (LLPC, zwitterionic) micelles. Moreover, the tilt angle of an assumed helical portion of the peptide is similar in both systems. In previous work we proposed that TRP3 acts by a toroidal pore mechanism. In view of the high hydrophobic core exposure, hydration, and curvature presented by micelles, the conformation of TRP3 in these systems could be related to the peptide's conformation in the toroidal pore.
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Baldissera G, dos Santos Cabrera MP, Chahine J, Ruggiero JR. Role of Peptide–Peptide Interactions in Aggregation: Protonectins Observed in Equilibrium and Replica Exchange Molecular Dynamics Simulations. Biochemistry 2015; 54:2262-9. [DOI: 10.1021/bi501210e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gisele Baldissera
- Faculdade de Tecnologia de Catanduva, 15800-020 Catanduva, SP, Brazil
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