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Costa ISD, Junot T, Silva FL, Felix W, Cardozo Fh JL, Pereira de Araujo AF, Pais do Amaral C, Gonçalves S, Santos NC, Leite JRSA, Bloch C, Brand GD. Occurrence and evolutionary conservation analysis of α-helical cationic amphiphilic segments in the human proteome. FEBS J 2024; 291:547-565. [PMID: 37945538 DOI: 10.1111/febs.16997] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/14/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
The existence of encrypted fragments with antimicrobial activity in human proteins has been thoroughly demonstrated in the literature. Recently, algorithms for the large-scale identification of these segments in whole proteomes were developed, and the pervasiveness of this phenomenon was stated. These algorithms typically mine encrypted cationic and amphiphilic segments of proteins, which, when synthesized as individual polypeptide sequences, exert antimicrobial activity by membrane disruption. In the present report, the human reference proteome was submitted to the software kamal for the uncovering of protein segments that correspond to putative intragenic antimicrobial peptides (IAPs). The assessment of the identity of these segments, frequency, functional classes of parent proteins, structural relevance, and evolutionary conservation of amino acid residues within their corresponding proteins was conducted in silico. Additionally, the antimicrobial and anticancer activity of six selected synthetic peptides was evaluated. Our results indicate that cationic and amphiphilic segments can be found in 2% of all human proteins, but are more common in transmembrane and peripheral membrane proteins. These segments are surface-exposed basic patches whose amino acid residues present similar conservation scores to other residues with similar solvent accessibility. Moreover, the antimicrobial and anticancer activity of the synthetic putative IAP sequences was irrespective to whether these are associated to membranes in the cellular setting. Our study discusses these findings in light of the current understanding of encrypted peptide sequences, offering some insights into the relevance of these segments to the organism in the context of their harboring proteins or as separate polypeptide sequences.
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Affiliation(s)
- Igor S D Costa
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Tiago Junot
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Fernanda L Silva
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
| | - Wanessa Felix
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada - NuPMIA, Faculdade de Medicina, Universidade de Brasília, Brazil
| | - José L Cardozo Fh
- Laboratório de Espectrometria de Massa - LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil
| | - Antonio F Pereira de Araujo
- Laboratório de Biofísica Teórica e Computacional, Departamento de Biologia Celular, Universidade de Brasília, Brazil
| | | | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Nuno C Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - José R S A Leite
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada - NuPMIA, Faculdade de Medicina, Universidade de Brasília, Brazil
| | - Carlos Bloch
- Laboratório de Espectrometria de Massa - LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Brazil
| | - Guilherme D Brand
- Laboratório de Síntese e Análise de Biomoléculas - LSAB, Instituto de Química, Universidade de Brasília, Brazil
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Jarrin M, Kalligeraki AA, Uwineza A, Cawood CS, Brown AP, Ward EN, Le K, Freitag-Pohl S, Pohl E, Kiss B, Tapodi A, Quinlan RA. Independent Membrane Binding Properties of the Caspase Generated Fragments of the Beaded Filament Structural Protein 1 (BFSP1) Involves an Amphipathic Helix. Cells 2023; 12:1580. [PMID: 37371051 DOI: 10.3390/cells12121580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND BFSP1 (beaded filament structural protein 1) is a plasma membrane, Aquaporin 0 (AQP0/MIP)-associated intermediate filament protein expressed in the eye lens. BFSP1 is myristoylated, a post-translation modification that requires caspase cleavage at D433. Bioinformatic analyses suggested that the sequences 434-452 were α-helical and amphipathic. METHODS AND RESULTS By CD spectroscopy, we show that the addition of trifluoroethanol induced a switch from an intrinsically disordered to a more α-helical conformation for the residues 434-467. Recombinantly produced BFSP1 fragments containing this amphipathic helix bind to lens lipid bilayers as determined by surface plasmon resonance (SPR). Lastly, we demonstrate by transient transfection of non-lens MCF7 cells that these same BFSP1 C-terminal sequences localise to plasma membranes and to cytoplasmic vesicles. These can be co-labelled with the vital dye, lysotracker, but other cell compartments, such as the nuclear and mitochondrial membranes, were negative. The N-terminal myristoylation of the amphipathic helix appeared not to change either the lipid affinity or membrane localisation of the BFSP1 polypeptides or fragments we assessed by SPR and transient transfection, but it did appear to enhance its helical content. CONCLUSIONS These data support the conclusion that C-terminal sequences of human BFSP1 distal to the caspase site at G433 have independent membrane binding properties via an adjacent amphipathic helix.
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Affiliation(s)
- Miguel Jarrin
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
| | - Alexia A Kalligeraki
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
| | - Alice Uwineza
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
| | - Chris S Cawood
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
| | - Adrian P Brown
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
| | - Edward N Ward
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
| | - Khoa Le
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Stefanie Freitag-Pohl
- Department of Chemistry, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK
| | - Ehmke Pohl
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
- Department of Chemistry, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK
| | - Bence Kiss
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pécs, 7624 Pécs, Hungary
| | - Antal Tapodi
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pécs, 7624 Pécs, Hungary
| | - Roy A Quinlan
- Department of Biosciences, Upper Mountjoy Science Site, The University of Durham, South Road, Durham DH1 3LE, UK
- Biophysical Sciences Institute, Durham University, Upper Mountjoy, South Road, Durham DH1 3LE, UK
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
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Keller RCA. The role and significance of potential lipid-binding regions in the mitochondrial protein import motor: an in-depth in silico study. 3 Biotech 2015; 5:1041-1051. [PMID: 28324412 PMCID: PMC4624131 DOI: 10.1007/s13205-015-0310-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 05/12/2015] [Indexed: 12/05/2022] Open
Abstract
Over the last two decades, an impressive progress has been made in the identification of novel factors in the translocation machineries of the mitochondrial protein import and their possible roles. The role of lipids and possible protein–lipids interactions remains a relatively unexplored territory. Investigating the role of potential lipid-binding regions in the sub-units of the mitochondrial motor might help to shed some more light in our understanding of protein–lipid interactions mechanistically. Bioinformatics results seem to indicate multiple potential lipid-binding regions in each of the sub-units. The subsequent characterization of some of those regions in silico provides insight into the mechanistic functioning of this intriguing and essential part of the protein translocation machinery. Details about the way the regions interact with phospholipids were found by the use of Monte Carlo simulations. For example, Pam18 contains one possible transmembrane region and two tilted surface bound conformations upon interaction with phospholipids. The results demonstrate that the presented bioinformatics approach might be useful in an attempt to expand the knowledge of the possible role of protein–lipid interactions in the mitochondrial protein translocation process.
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Affiliation(s)
- Rob C A Keller
- Section Chemistry, Charlemagne College, Wilhelminastraat 13-15, 6524 AJ, Nijmegen, The Netherlands.
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