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Afrose F, McKay MJ, Mortazavi A, Suresh Kumar V, Greathouse DV, Koeppe RE. Transmembrane Helix Integrity versus Fraying To Expose Hydrogen Bonds at a Membrane-Water Interface. Biochemistry 2019; 58:633-645. [PMID: 30565458 DOI: 10.1021/acs.biochem.8b01119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Transmembrane helices dominate the landscape for many membrane proteins. Often flanked by interfacial aromatic residues, these transmembrane helices also contain loops and interhelix segments, which could help in stabilizing a transmembrane orientation. Using 2H nuclear magnetic resonance spectroscopy to monitor bilayer-incorporated model GWALP23 family peptides, we address systematically the issue of helix fraying in relation to the dynamics and orientation of highly similar individual transmembrane helices. We inserted aromatic (Phe, Trp, Tyr, and His) or non-aromatic residues (Ala and Gly) into positions 4 and 5 adjacent to a core transmembrane helix to examine the side-chain dependency of the transmembrane orientation, dynamics, and helix integrity (extent and location of unraveling). Incorporation of [2H]alanine labels enables one to assess the helicity of the core sequence and the peptide termini. For most of the helices, we observed substantial unwinding involving at least three residues at both ends. For the unique case of histidine at positions 4 and 5, an extended N-terminal unwinding was observed up to residue 7. For further investigation of the onset of fraying, we employed A4,5GWALP23 with 2H labels at residues 4 and 5 and found that the number of terminal residues involved in the unwinding depends on bilayer thicknesses and helps to govern the helix dynamics. The combined results enable us to compare and contrast the extent of fraying for each related helix, as reflected by the deviation of experimental 2H quadrupolar splitting magnitudes of juxta-terminal alanines A3 and A21 from those represented by an ideal helix geometry.
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Affiliation(s)
- Fahmida Afrose
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
| | - Matthew J McKay
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
| | - Armin Mortazavi
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
| | - Vasupradha Suresh Kumar
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
| | - Denise V Greathouse
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry , University of Arkansas , Fayetteville , Arkansas 72701 , United States
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2
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Alves DS, Westerfield JM, Shi X, Nguyen VP, Stefanski KM, Booth KR, Kim S, Morrell-Falvey J, Wang BC, Abel SM, Smith AW, Barrera FN. A novel pH-dependent membrane peptide that binds to EphA2 and inhibits cell migration. eLife 2018; 7:36645. [PMID: 30222105 PMCID: PMC6192698 DOI: 10.7554/elife.36645] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/16/2018] [Indexed: 12/19/2022] Open
Abstract
Misregulation of the signaling axis formed by the receptor tyrosine kinase (RTK) EphA2 and its ligand, ephrinA1, causes aberrant cell-cell contacts that contribute to metastasis. Solid tumors are characterized by an acidic extracellular medium. We intend to take advantage of this tumor feature to design new molecules that specifically target tumors. We created a novel pH-dependent transmembrane peptide, TYPE7, by altering the sequence of the transmembrane domain of EphA2. TYPE7 is highly soluble and interacts with the surface of lipid membranes at neutral pH, while acidity triggers transmembrane insertion. TYPE7 binds to endogenous EphA2 and reduces Akt phosphorylation and cell migration as effectively as ephrinA1. Interestingly, we found large differences in juxtamembrane tyrosine phosphorylation and the extent of EphA2 clustering when comparing TYPE7 with activation by ephrinA1. This work shows that it is possible to design new pH-triggered membrane peptides to activate RTK and gain insights on its activation mechanism.
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Affiliation(s)
- Daiane S Alves
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States
| | - Justin M Westerfield
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States
| | - Xiaojun Shi
- Department of Chemistry, University of Akron, Akron, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States.,Pharmacology, Case Western Reserve University, Cleveland, United States.,Rammelkamp Center for Research, MetroHealth Medical Center, Cleveland, United States
| | - Vanessa P Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States
| | - Katherine M Stefanski
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, United States
| | - Kristen R Booth
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States
| | - Soyeon Kim
- Department of Chemistry, University of Akron, Akron, United States
| | - Jennifer Morrell-Falvey
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, United States
| | - Bing-Cheng Wang
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States.,Pharmacology, Case Western Reserve University, Cleveland, United States.,Rammelkamp Center for Research, MetroHealth Medical Center, Cleveland, United States
| | - Steven M Abel
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, United States.,National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, United States
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, United States
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, United States
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3
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Thibado JK, Martfeld AN, Greathouse DV, Koeppe RE. Influence of High pH and Cholesterol on Single Arginine-Containing Transmembrane Peptide Helices. Biochemistry 2016; 55:6337-6343. [PMID: 27782382 PMCID: PMC5266483 DOI: 10.1021/acs.biochem.6b00896] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
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An essential component
of mammalian cells, cholesterol exerts significant
influence on the physical properties of the cell membrane and in turn
its constituents, including membrane proteins. Although sparse, polar
amino acid residues are highly conserved in membrane proteins and
play pivotal roles in determining specific structural and functional
properties. To improve our understanding of particular polar residues
in the membrane environment, we have examined two specific “guest”
Arg residues within a well-defined and deuterium-labeled “host”
framework provided by the transmembrane helical peptide GWALP23 (acetyl-GGALWLALALALALALALWLAGA-amide).
Solid-state 2H nuclear magnetic resonance (NMR) spectra
from aligned bilayer membrane samples effectively report changes in
the host helix properties because of the incorporation of the guest
residues. The focus of this work is two-pronged. First, GWALP23-R14
was examined over a pH range of 2–13 in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) ester- or ether-linked
bilayer membranes. Our findings indicate that the Arg guanidinium
side chain remains charged over this entire range, in agreement with
numerous molecular dynamics simulations. Second, GWALP23-R12 and GWALP23-R14
peptides were characterized in DOPC bilayers with varying cholesterol
content. Our findings suggest that 10 or 20% cholesterol content has
minimal impact on the orientation of the R14 peptide. Although the
NMR signals are broader and weaker in the presence of 20% cholesterol,
the deuterium quadrupolar splittings for [2H]Ala residues
in GWALP23-R14 change very little. Conversely, cholesterol appears
to modulate the multistate behavior of GWALP23-R12 and to favor a
major interfacial state for the helix, bound at the bilayer surface.
These results indicate a conditional sensitivity of a complex multistate
transmembrane Arg-containing peptide helix to the presence of cholesterol.
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Affiliation(s)
- Jordana K Thibado
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Ashley N Martfeld
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Denise V Greathouse
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
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Oh KI, Smith-Dupont KB, Markiewicz BN, Gai F. Kinetics of peptide folding in lipid membranes. Biopolymers 2016; 104:281-90. [PMID: 25808575 DOI: 10.1002/bip.22640] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 02/12/2015] [Accepted: 02/14/2015] [Indexed: 12/31/2022]
Abstract
Despite our extensive understanding of water-soluble protein folding kinetics, much less is known about the folding dynamics and mechanisms of membrane proteins. However, recent studies have shown that for relatively simple systems, such as peptides that form a transmembrane α-helix, helical dimer, or helix-turn-helix, it is possible to assess the kinetics of several important steps, including peptide binding to the membrane from aqueous solution, peptide folding on the membrane surface, helix insertion into the membrane, and helix-helix association inside the membrane. Herein, we provide a brief review of these studies and also suggest new initiation and probing methods that could lead to improved temporal and structural resolution in future experiments.
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Affiliation(s)
- Kwang-Im Oh
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Kathryn B Smith-Dupont
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
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Pimenta J, Viegas A, Sardinha J, Martins IC, Cabrita EJ, Fontes CMGA, Prates JA, Pereira RMLN. NMR solution structure and SRP54M predicted interaction of the N-terminal sequence (1-30) of the ovine Doppel protein. Peptides 2013; 49:32-40. [PMID: 23973967 DOI: 10.1016/j.peptides.2013.08.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 01/29/2023]
Abstract
Prion protein (PrP(C)) biosynthesis involves a multi-step process that includes translation and post-translational modifications. While PrP has been widely investigated, for the homolog Doppel (Dpl), limited knowledge is available. In this study, we focused on a vital step of eukaryotic protein biosynthesis: targeting by the signal recognition particle (SRP). Taking the ovine Dpl (OvDpl(1-30)) peptide as a template, we studied its behavior in two different hydrophobic environments using CD and NMR spectroscopy. In both trifluoroethanol (TFE) and dihexanoyl-sn-glycero-3-phosphatidylcholine (DHPC), the OvDpl(1-30) peptide revealed to fold in an alpha-helical conformation with a well-defined central region extending from residue Cys8 until Ser22. The NMR structure was subsequently included in a computational docking complex with the conserved M-domain of SRP54 protein (SRP54M), and further compared with the N-terminal structures of mouse Dpl and bovine PrP(C) proteins. This allowed the determination of (i) common predicted N-terminal/SRP54M polar contacts (Asp331, Gln335, Glu365 and Lys432) and (ii) different N-C orientations between prion and Dpl peptides at the SRP54M hydrophobic groove, that are in agreement with each peptide electrostatic potential. Together, these findings provide new insights into the biosynthesis of prion-like proteins. Besides they also show the role of protein conformational switches in signalization toward the endoplasmic membrane, a key event of major significance in the cell cycle. They are thus of general applicability to the study of the biological function of prion-like as well as other proteins.
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Affiliation(s)
- Jorge Pimenta
- Unidade de Biotecnologia e Recursos Genéticos, Instituto Nacional de Investigação Agrária e Veterinária, Quinta da Fonte Boa, Vale de Santarém, Portugal; CIISA, Faculdade de Medicina Veterinária (FMV), Universidade Técnica de Lisboa, Lisbon, Portugal
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Peptide-lipid interactions: experiments and applications. Int J Mol Sci 2013; 14:18758-89. [PMID: 24036440 PMCID: PMC3794806 DOI: 10.3390/ijms140918758] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 02/06/2023] Open
Abstract
The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary.
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