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Guimarães CFRC, Félix AS, Brandão TAS, Bemquerer MP, Piló-Veloso D, Verly RM, Resende JM. Optimizing the synthesis of dimeric peptides: influence of the reaction medium and effects that modulate kinetics and reaction yield. Amino Acids 2023; 55:1201-1212. [PMID: 37543997 DOI: 10.1007/s00726-023-03309-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023]
Abstract
Peptides are remarkably interesting alternatives to several applications. In particular, antimicrobial sequences have raised major interest of the scientific community due to the resistance acquired by commonly used antibiotics. Amongst these, some dimeric peptides have shown very promising characteristics as strong biological activities and resistance against degradation by peptidases. However, despite such promising characteristics, a relatively small number of studies address dimeric peptides, mainly due to the synthesis-related obstacles in their production, whereas the well-implemented routines of solid phase peptide synthesis-which includes the possibility of automation-makes life significantly easier. Here, we present kinetic investigations of the dimerization of a cysteine-containing sequence to obtain the homodimeric antimicrobial peptide homotarsinin. Based on the structural and membrane interaction data already available for the dimer and its monomeric chain, we have proposed distinct dimerization protocols in selected environments, namely, aqueous buffer, TFE:H2O and micellar solutions. The experimental results were adjusted by a theoretical model. Both the kinetic profiles and the reaction yields are dependent on the reaction medium, clearly indicating that aggregation, peptide structure, and peptide-membrane interactions play major roles in the formation of the disulfide bond. Finally, the rationalization of the different aspects addressed here is expected to contribute to research and applications that demand the obtainment of dimeric peptides.
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Affiliation(s)
- Carlos F R C Guimarães
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, Belo Horizonte, MG, 31270-901, Brazil
- Present Address: Universidade Nilton Lins, Avenida Professor Nilton Lins, Manaus, AM, 69058-030, Brazil
| | - Amanda S Félix
- Departamento de Química, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, 39100-000, Brazil
| | - Tiago A S Brandão
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, Belo Horizonte, MG, 31270-901, Brazil
| | - Marcelo P Bemquerer
- Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Embrapa Gado de Leite, Juiz de Fora, MG, 36038-330, Brazil
| | - Dorila Piló-Veloso
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, Belo Horizonte, MG, 31270-901, Brazil
| | - Rodrigo M Verly
- Departamento de Química, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, 39100-000, Brazil.
| | - Jarbas M Resende
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, P.O. Box 486, Belo Horizonte, MG, 31270-901, Brazil.
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Moreira Brito JC, Carvalho LR, Neves de Souza A, Carneiro G, Magalhães PP, Farias LM, Guimarães NR, Verly RM, Resende JM, Elena de Lima M. PEGylation of the antimicrobial peptide LyeTx I-b maintains structure-related biological properties and improves selectivity. Front Mol Biosci 2022; 9:1001508. [PMID: 36310605 PMCID: PMC9611540 DOI: 10.3389/fmolb.2022.1001508] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 09/20/2022] [Indexed: 07/31/2023] Open
Abstract
The biological activity of antimicrobial peptides and proteins is closely related to their structural aspects and is sensitive to certain post-translational modifications such as glycosylation, lipidation and PEGylation. However, PEGylation of protein and peptide drugs has expanded in recent years due to the reduction of their toxicity. Due to their size, the PEGylation process can either preserve or compromise the overall structure of these biopolymers and their biological properties. The antimicrobial peptide LyeTx I-bcys was synthesized by Fmoc strategy and coupled to polyethylene glycol 2.0 kDa. The conjugates were purified by HPLC and characterized by MALDI-ToF-MS analysis. Microbiological assays with LyeTx I-bcys and LyeTx I-bPEG were performed against Staphylococcus aureus (ATCC 33591) and Escherichia coli (ATCC 25922) in liquid medium. MIC values of 2.0 and 1.0 µM for LyeTx I-bcys and 8.0 and 4.0 µM for LyeTx I-bPEG were observed against S. aureus and E. coli, respectively. PEGylation of LyeTx I-bcys (LyeTx I-bPEG) decreased the cytotoxicity determined by MTT method for VERO cells compared to the non-PEGylated peptide. In addition, structural and biophysical studies were performed to evaluate the effects of PEGylation on the nature of peptide-membrane interactions. Surface Plasmon Resonance experiments showed that LyeTx I-b binds to anionic membranes with an association constant twice higher than the PEGylated form. The three-dimensional NMR structures of LyeTx I-bcys and LyeTx I-bPEG were determined and compared with the LyeTx I-b structure, and the hydrodynamic diameter and zeta potential of POPC:POPG vesicles were similar upon the addition of both peptides. The mPEG-MAL conjugation of LyeTx I-bcys gave epimers, and it, together with LyeTx I-bPEG, showed clear α-helical profiles. While LyeTx I-bcys showed no significant change in amphipathicity compared to LyeTx I-b, LyeTx I-bPEG was found to have a slightly less clear separation between hydrophilic and hydrophobic faces. However, the similar conformational freedom of LyeTx I-b and LyeTx I-bPEG suggests that PEGylation does not cause significant structural changes. Overall, our structural and biophysical studies indicate that the PEGylation does not alter the mode of peptide interaction and maintains antimicrobial activity while minimizing tissue toxicity, which confirmed previous results obtained in vivo. Interestingly, significantly improved proteolytic resistance to trypsin and proteinase K was observed after PEGylation.
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Affiliation(s)
| | - Lucas Raposo Carvalho
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Amanda Neves de Souza
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil
| | - Guilherme Carneiro
- Departamento de Farmácia, Faculdade de Ciências Biológicas e da Saúde, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil
| | - Paula Prazeres Magalhães
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Luiz Macêdo Farias
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Natália Rocha Guimarães
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Rodrigo Moreira Verly
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil
| | - Jarbas Magalhães Resende
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria Elena de Lima
- Programa de Pós-graduação em Medicina e Biomedicina da Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
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Picturins and Pictuseptins, two novel antimicrobial peptide families from the skin secretions of the Chachi treefrog, Boana picturata. J Proteomics 2022; 264:104633. [DOI: 10.1016/j.jprot.2022.104633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/24/2022] [Accepted: 05/16/2022] [Indexed: 11/21/2022]
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Schistocins: Novel antimicrobial peptides encrypted in the Schistosoma mansoni Kunitz Inhibitor SmKI-1. Biochim Biophys Acta Gen Subj 2021; 1865:129989. [PMID: 34389467 DOI: 10.1016/j.bbagen.2021.129989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/30/2021] [Accepted: 08/06/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Here we describe a new class of cryptides (peptides encrypted within a larger protein) with antimicrobial properties, named schistocins, derived from SmKI-1, a key protein in Shistosoma mansoni survival. This is a multi-functional protein with biotechnological potential usage as a therapeutic molecule in inflammatory diseases and to control schistosomiasis. METHODS We used our algorithm enCrypted, to perform an in silico proteolysis of SmKI-1 and a screening for potential antimicrobial activity. The selected peptides were chemically synthesized, tested in vitro and evaluated by both structural (CD, NMR) and biophysical (ITC) studies to access their structure-function relationship. RESULTS EnCrypted was capable of predicting AMPs in SmKI-1. Our biophysical analyses described a membrane-induced conformational change from random coil-to-α-helix and a peptide-membrane equilibrium for all schistocins. Our structural data allowed us to suggest a well-known mode of peptide-membrane interaction in which electrostatic attraction between the cationic peptides and anionic membranes results in the bilayer disordering. Moreover, the NMR exchange H/D data with the higher entropic contribution observed for the peptide-membrane interaction showed that shistocins have different orientations upon the membrane. CONCLUSIONS This work demonstrate the robustness for using the physicochemical features of predicted peptides in the identification of new bioactive cryptides besides the relevance of combining these analyses with biophysical methods to understand the peptide-membrane affinity and improve further algorithms. GENERAL SIGNIFICANCE Bioprospecting cryptides can be conducted through data mining of protein databases demonstrating the success of our strategy. The peptides-based agents derived from SmKI-1 might have high impact for system-biology and biotechnology.
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