The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer
PMAP-23, a cathelicidin-derived host defense peptide, does not cause severe membrane permeabilization, but exerts strong and broad-spectrum bactericidal activity. We have previously shown that it forms an amphipathic α-helical structure with a central hinge induced by the PXXP motif, which is implic...
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MDPI AG
2021-09-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/18/9752 |
| _version_ | 1797518938229178368 |
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| author | Sung-Tae Yang Song-Yub Shin Sung-Heui Shin |
| author_facet | Sung-Tae Yang Song-Yub Shin Sung-Heui Shin |
| author_sort | Sung-Tae Yang |
| collection | DOAJ |
| description | PMAP-23, a cathelicidin-derived host defense peptide, does not cause severe membrane permeabilization, but exerts strong and broad-spectrum bactericidal activity. We have previously shown that it forms an amphipathic α-helical structure with a central hinge induced by the PXXP motif, which is implicated in the interaction of PMAP-23 with negatively charged bacterial membranes. Here, we studied the potential roles of the PXXP motif in PMAP-23 translocation across the lipid bilayer by replacing Pro residues with either α-helix former Ala (PMAP-PA) or α-helix breaker Gly (PMAP-PG). Although both PMAP-PA and PMAP-PG led to effective membrane depolarization and permeabilization, they showed less antimicrobial activity than wild-type PMAP-23. Interestingly, we observed that PMAP-23 crossed lipid bilayers much more efficiently than its Pro-substituted derivatives. The fact that the Gly-induced hinge was unable to replace the PXXP motif in PMAP-23 translocation suggests that the PXXP motif has unique structural properties other than the central hinge. Surface plasmon resonance sensorgrams showed that the running buffer almost entirely dissociated PMAP-23 from the membrane surface, while its Pro-substituted derivatives remained significantly bound to the membrane. In addition, kinetic analysis of the sensorgrams revealed that the central PXXP motif allows PMAP-23 to rapidly translocate at the interface between the hydrophilic and hydrophobic phases. Taken together, we propose that the structural and kinetic understanding of the PXXP motif in peptide translocation could greatly aid the development of novel antimicrobial peptides with intracellular targets by promoting peptide entry into bacterial cells. |
| first_indexed | 2024-03-10T07:35:24Z |
| format | Article |
| id | doaj.art-0149cf13d34f4064918fc7d4dec3183a |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T07:35:24Z |
| publishDate | 2021-09-01 |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-0149cf13d34f4064918fc7d4dec3183a2023-11-22T13:27:00ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-09-012218975210.3390/ijms22189752The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid BilayerSung-Tae Yang0Song-Yub Shin1Sung-Heui Shin2Department of Microbiology, School of Medicine, Chosun University, Gwangju 61452, KoreaDepartment of Cellular and Molecular Medicine, School of Medicine, Chosun University, Gwangju 61452, KoreaDepartment of Microbiology, School of Medicine, Chosun University, Gwangju 61452, KoreaPMAP-23, a cathelicidin-derived host defense peptide, does not cause severe membrane permeabilization, but exerts strong and broad-spectrum bactericidal activity. We have previously shown that it forms an amphipathic α-helical structure with a central hinge induced by the PXXP motif, which is implicated in the interaction of PMAP-23 with negatively charged bacterial membranes. Here, we studied the potential roles of the PXXP motif in PMAP-23 translocation across the lipid bilayer by replacing Pro residues with either α-helix former Ala (PMAP-PA) or α-helix breaker Gly (PMAP-PG). Although both PMAP-PA and PMAP-PG led to effective membrane depolarization and permeabilization, they showed less antimicrobial activity than wild-type PMAP-23. Interestingly, we observed that PMAP-23 crossed lipid bilayers much more efficiently than its Pro-substituted derivatives. The fact that the Gly-induced hinge was unable to replace the PXXP motif in PMAP-23 translocation suggests that the PXXP motif has unique structural properties other than the central hinge. Surface plasmon resonance sensorgrams showed that the running buffer almost entirely dissociated PMAP-23 from the membrane surface, while its Pro-substituted derivatives remained significantly bound to the membrane. In addition, kinetic analysis of the sensorgrams revealed that the central PXXP motif allows PMAP-23 to rapidly translocate at the interface between the hydrophilic and hydrophobic phases. Taken together, we propose that the structural and kinetic understanding of the PXXP motif in peptide translocation could greatly aid the development of novel antimicrobial peptides with intracellular targets by promoting peptide entry into bacterial cells.https://www.mdpi.com/1422-0067/22/18/9752antimicrobial peptidePMAP-23PXXP motiftranslocationmembrane disruption |
| spellingShingle | Sung-Tae Yang Song-Yub Shin Sung-Heui Shin The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer International Journal of Molecular Sciences antimicrobial peptide PMAP-23 PXXP motif translocation membrane disruption |
| title | The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer |
| title_full | The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer |
| title_fullStr | The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer |
| title_full_unstemmed | The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer |
| title_short | The Central PXXP Motif Is Crucial for PMAP-23 Translocation across the Lipid Bilayer |
| title_sort | central pxxp motif is crucial for pmap 23 translocation across the lipid bilayer |
| topic | antimicrobial peptide PMAP-23 PXXP motif translocation membrane disruption |
| url | https://www.mdpi.com/1422-0067/22/18/9752 |
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