1
|
Strandberg E, Wadhwani P, Bürck J, Anders P, Mink C, van den Berg J, Ciriello RAM, Melo MN, Castanho MARB, Bardají E, Ulmschneider JP, Ulrich AS. Temperature-Dependent Re-alignment of the Short Multifunctional Peptide BP100 in Membranes Revealed by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations. Chembiochem 2023; 24:e202200602. [PMID: 36454659 DOI: 10.1002/cbic.202200602] [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: 10/20/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/02/2022]
Abstract
BP100 is a cationic undecamer peptide with antimicrobial and cell-penetrating activities. The orientation of this amphiphilic α-helix in lipid bilayers was examined under numerous conditions using solid-state 19 F, 15 N and 2 H NMR. At high temperatures in saturated phosphatidylcholine lipids, BP100 lies flat on the membrane surface, as expected. Upon lowering the temperature towards the lipid phase transition, the helix is found to flip into an upright transmembrane orientation. In thin bilayers, this inserted state was stable at low peptide concentration, but thicker membranes required higher peptide concentrations. In the presence of lysolipids, the inserted state prevailed even at high temperature. Molecular dynamics simulations suggest that BP100 monomer insertion can be stabilized by snorkeling lysine side chains. These results demonstrate that even a very short helix like BP100 can span (and thereby penetrate through) a cellular membrane under suitable conditions.
Collapse
Affiliation(s)
- Erik Strandberg
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany
| | - Parvesh Wadhwani
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany
| | - Jochen Bürck
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany
| | - Patrick Anders
- Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Christian Mink
- Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.,Present address: Syngenta Crop Protection AG, 4333, Münchwilen, Switzerland
| | - Jonas van den Berg
- Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Raffaele A M Ciriello
- Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Manuel N Melo
- Instituto de Medicina Molecular Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisbon, Portugal.,Present address: ITQB Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular Faculdade de Medicina, Universidade de Lisboa, 1649-028, Lisbon, Portugal
| | - Eduard Bardají
- LIPPSO, Department of Chemistry, University of Girona, Campus Montilivi, 17071, Girona, Spain
| | - Jakob P Ulmschneider
- Institute of Natural Sciences and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Anne S Ulrich
- Karlsruhe Institute of Technology (KIT), Institute of Biological Interfaces (IBG-2), POB 3640, 76021, Karlsruhe, Germany.,Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| |
Collapse
|
2
|
Michurin OM, Tolmachova K, Afonin S, Babii O, Grage SL, Ulrich AS, Komarov IV, Radchenko DS. Conformationally Constrained Mono-Fluorinated Arginine as a Cationic Label for Solid-State 19
F NMR Analysis of Membrane-Bound Peptides. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kateryna Tolmachova
- Enamine Ltd.; vul. Chervonotkatska 78 02094 Kyiv Ukraine
- Institute of Bioorganic Chemistry and Petrochemistry; National Academy of Sciences of Ukraine; vul. Murmanska 1 02660 Kyiv Ukraine
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2); Karlsruhe Institute of Technology (KIT); POB 3640 76021 Karlsruhe Germany
| | - Oleg Babii
- Institute of Organic Chemistry (IOC); KIT; Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Stephan L. Grage
- Institute of Biological Interfaces (IBG-2); Karlsruhe Institute of Technology (KIT); POB 3640 76021 Karlsruhe Germany
| | - Anne S. Ulrich
- Institute of Biological Interfaces (IBG-2); Karlsruhe Institute of Technology (KIT); POB 3640 76021 Karlsruhe Germany
- Institute of Organic Chemistry (IOC); KIT; Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Igor V. Komarov
- Taras Shevchenko National University of Kyiv; Taras Shevchenko National University of Kyiv; vul. Volodymyrska 60 01601 Kyiv Ukraine
| | - Dmytro S. Radchenko
- Enamine Ltd.; vul. Chervonotkatska 78 02094 Kyiv Ukraine
- Taras Shevchenko National University of Kyiv; Taras Shevchenko National University of Kyiv; vul. Volodymyrska 60 01601 Kyiv Ukraine
| |
Collapse
|
3
|
Grage SL, Afonin S, Kara S, Buth G, Ulrich AS. Membrane Thinning and Thickening Induced by Membrane-Active Amphipathic Peptides. Front Cell Dev Biol 2016; 4:65. [PMID: 27595096 PMCID: PMC4999517 DOI: 10.3389/fcell.2016.00065] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/09/2016] [Indexed: 11/13/2022] Open
Abstract
Membrane thinning has been discussed as a fundamental mechanism by which antimicrobial peptides can perturb cellular membranes. To understand which factors play a role in this process, we compared several amphipathic peptides with different structures, sizes and functions in their influence on the lipid bilayer thickness. PGLa and magainin 2 from X. laevis were studied as typical representatives of antimicrobial cationic amphipathic α-helices. A 1:1 mixture of these peptides, which is known to possess synergistically enhanced activity, allowed us to evaluate whether and how this synergistic interaction correlates with changes in membrane thickness. Other systems investigated here include the α-helical stress-response peptide TisB from E. coli (which forms membrane-spanning dimers), as well as gramicidin S from A. migulanus (a natural antibiotic), and BP100 (designer-made antimicrobial and cell penetrating peptide). The latter two are very short, with a circular β-pleated and a compact α-helical structure, respectively. Solid-state (2)H-NMR and grazing incidence small angle X-ray scattering (GISAXS) on oriented phospholipid bilayers were used as complementary techniques to access the hydrophobic thickness as well as the bilayer-bilayer repeat distance including the water layer in between. This way, we found that magainin 2, gramicidin S, and BP100 induced membrane thinning, as expected for amphiphilic peptides residing in the polar/apolar interface of the bilayer. PGLa, on the other hand, decreased the hydrophobic thickness only at very high peptide:lipid ratios, and did not change the bilayer-bilayer repeat distance. TisB even caused an increase in the hydrophobic thickness and repeat distance. When reconstituted as a mixture, PGLa and magainin 2 showed a moderate thinning effect which was less than that of magainin 2 alone, hence their synergistically enhanced activity does not seem to correlate with a modulation of membrane thickness. Overall, the absence of a typical thinning response in the case of PGLa, and the increase in the repeat distance and membrane thickening observed for TisB, demonstrate that the concept of peptide-induced membrane thinning cannot be generalized. Instead, these results suggest that different factors contribute to the resulting changes in membrane thickness, such as the peptide orientation in the bilayer, and/or bilayer adaptation to hydrophobic mismatch.
Collapse
Affiliation(s)
- Stephan L Grage
- Karlsruhe Institute of Technology, Institute of Biological Interfaces Karlsruhe, Germany
| | - Sergii Afonin
- Karlsruhe Institute of Technology, Institute of Biological Interfaces Karlsruhe, Germany
| | - Sezgin Kara
- Karlsruhe Institute of Technology, Institute of Organic Chemistry Karlsruhe, Germany
| | - Gernot Buth
- Karlsruhe Institute of Technology, Institute for Accelerator Physics and Technology Karlsruhe, Germany
| | - Anne S Ulrich
- Karlsruhe Institute of Technology, Institute of Biological InterfacesKarlsruhe, Germany; Karlsruhe Institute of Technology, Institute of Organic ChemistryKarlsruhe, Germany
| |
Collapse
|
4
|
Fillion M, Auger M. Oriented samples: a tool for determining the membrane topology and the mechanism of action of cationic antimicrobial peptides by solid-state NMR. Biophys Rev 2015; 7:311-320. [PMID: 28510228 PMCID: PMC5425733 DOI: 10.1007/s12551-015-0167-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/05/2015] [Indexed: 01/12/2023] Open
Abstract
Overuse and misuse of antibiotics have led bacteria to acquire several mechanisms of resistance. In response to this, researchers have identified natural antimicrobial peptides as promising candidates to fight against multiresistant bacteria. However, their mode of action is still unclear, and a better understanding of the mode of action of these peptides is of primary importance to develop new peptides displaying high antibacterial activity and low hemolytic activity. One of the main features that defines the mechanism of action is the membrane topology of the peptide. Among the spectroscopic techniques, solid-state NMR is the technique of choice for determining the location of the peptide within the membrane. It can be achieved by performing experiments with oriented samples. In the literature, the two most common types of oriented samples are bicelles and phospholipids mechanically oriented between glass plates. The mode of perturbation of the membrane-active peptide can be studied by phosphorus-31 and deuterium NMR. On the other hand, several experiments such as nitrogen-15 and fluorine solid-state NMR, that require labeled peptides, can give valuable information on the membrane topology of the peptide. The combination of the latter techniques allows the determination of a precise topology, thus a better knowledge of the molecular determinants involved in the membrane interactions of antimicrobial peptides.
Collapse
Affiliation(s)
- Matthieu Fillion
- Department of Chemistry, Regroupement québécois de recherche sur la fonction, la structure et l'ingénierie des protéines (PROTEO), Centre de recherche sur les matériaux avancés (CERMA), Centre québécois sur les matériaux fonctionnels (CQMF), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Michèle Auger
- Department of Chemistry, Regroupement québécois de recherche sur la fonction, la structure et l'ingénierie des protéines (PROTEO), Centre de recherche sur les matériaux avancés (CERMA), Centre québécois sur les matériaux fonctionnels (CQMF), Université Laval, Québec, QC, G1V 0A6, Canada.
| |
Collapse
|
5
|
Control and role of pH in peptide–lipid interactions in oriented membrane samples. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:833-41. [DOI: 10.1016/j.bbamem.2014.12.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 12/22/2022]
|
6
|
3D hydrophobic moment vectors as a tool to characterize the surface polarity of amphiphilic peptides. Biophys J 2015; 106:2385-94. [PMID: 24896117 DOI: 10.1016/j.bpj.2014.04.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 04/02/2014] [Accepted: 04/07/2014] [Indexed: 11/22/2022] Open
Abstract
The interaction of membranes with peptides and proteins is largely determined by their amphiphilic character. Hydrophobic moments of helical segments are commonly derived from their two-dimensional helical wheel projections, and the same is true for β-sheets. However, to the best of our knowledge, there exists no method to describe structures in three dimensions or molecules with irregular shape. Here, we define the hydrophobic moment of a molecule as a vector in three dimensions by evaluating the surface distribution of all hydrophilic and lipophilic regions over any given shape. The electrostatic potential on the molecular surface is calculated based on the atomic point charges. The resulting hydrophobic moment vector is specific for the instantaneous conformation, and it takes into account all structural characteristics of the molecule, e.g., partial unfolding, bending, and side-chain torsion angles. Extended all-atom molecular dynamics simulations are then used to calculate the equilibrium hydrophobic moments for two antimicrobial peptides, gramicidin S and PGLa, under different conditions. We show that their effective hydrophobic moment vectors reflect the distribution of polar and nonpolar patches on the molecular surface and the calculated electrostatic surface potential. A comparison of simulations in solution and in lipid membranes shows how the peptides undergo internal conformational rearrangement upon binding to the bilayer surface. A good correlation with solid-state NMR data indicates that the hydrophobic moment vector can be used to predict the membrane binding geometry of peptides. This method is available as a web application on http://www.ibg.kit.edu/HM/.
Collapse
|
7
|
Grage SL, Xu X, Schmitt M, Wadhwani P, Ulrich AS. (19)F-Labeling of Peptides Revealing Long-Range NMR Distances in Fluid Membranes. J Phys Chem Lett 2014; 5:4256-4259. [PMID: 26273971 DOI: 10.1021/jz502195t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
NMR distance measurements lie at the heart of structural biology. However, long-range distances could not yet be detected in liquid-crystalline biomembranes, because dipolar couplings are partially averaged by the intrinsic molecular mobility. Using conformationally constrained (19)F-labeled amino acids as reporter groups, we could more than double the accessible interatomic distance range by combining a highly sensitive solid-state multipulse (19)F-NMR scheme with a favorable sample geometry. Two rigid 4F-phenylglycine labels were placed into the helical antimicrobial peptide PGLa embedded in fluid oriented membrane samples. A modified Carr-Purcell-Meiboom-Gill sequence yielded an intramolecular distance of 6.6 Å for the labels spanning one helix turn, and 11.0 Å was obtained when the labels spanned two turns. This approach should now also allow the characterization of conformational changes in membrane-active peptides and of oligomeric assemblies in a biologically relevant lipid environment.
Collapse
Affiliation(s)
- Stephan L Grage
- †Institute of Biological Interfaces IBG-2, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Xiaojun Xu
- ‡Institute of Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Markus Schmitt
- †Institute of Biological Interfaces IBG-2, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Parvesh Wadhwani
- †Institute of Biological Interfaces IBG-2, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Anne S Ulrich
- †Institute of Biological Interfaces IBG-2, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
- ‡Institute of Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| |
Collapse
|
8
|
Tkachenko AN, Mykhailiuk PK, Radchenko DS, Babii O, Afonin S, Ulrich AS, Komarov IV. Design and Synthesis of a Monofluoro-Substituted Aromatic Amino Acid as a Conformationally Restricted19F NMR Label for Membrane-Bound Peptides. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301737] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
9
|
Tkachenko AN, Mykhailiuk PK, Afonin S, Radchenko DS, Kubyshkin VS, Ulrich AS, Komarov IV. A19F NMR Label to Substitute Polar Amino Acids in Peptides: A CF3-Substituted Analogue of Serine and Threonine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201208069] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
10
|
Tkachenko AN, Mykhailiuk PK, Afonin S, Radchenko DS, Kubyshkin VS, Ulrich AS, Komarov IV. A 19F NMR label to substitute polar amino acids in peptides: a CF3-substituted analogue of serine and threonine. Angew Chem Int Ed Engl 2012; 52:1486-9. [PMID: 23345130 DOI: 10.1002/anie.201208069] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Indexed: 11/09/2022]
Affiliation(s)
- Anton N Tkachenko
- Organic Chemistry Department, Taras Shevchenko National University of Kyiv, Volodymyrska 64, 01601 Kyiv, Ukraine
| | | | | | | | | | | | | |
Collapse
|
11
|
Dürr UHN, Afonin S, Hoff B, de Luca G, Emsley JW, Ulrich AS. Alignment of Druglike Compounds in Lipid Bilayers Analyzed by Solid-State 19F-NMR and Molecular Dynamics, Based on Dipolar Couplings of Adjacent CF3 Groups. J Phys Chem B 2012; 116:4769-82. [DOI: 10.1021/jp212339k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ulrich H. N. Dürr
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
| | - Sergii Afonin
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
| | - Barbara Hoff
- Bioprocess Engineering, IMVM, Fritz-Haber-Weg
2, 76131 Karlsruhe, Germany
| | - Giuseppina de Luca
- Dipartimento di Chimica, University of Calabria, Campus di Arcavacata, Via Pietro
Bucci Cubo 12C, I-87036 Rende (Cosenza), Italy
| | - James W. Emsley
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Anne S. Ulrich
- Institute
of Organic Chemistry
and CFN, Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg
6, 76131 Karlsruhe, Germany
| |
Collapse
|
12
|
Mykhailiuk PK, Voievoda NM, Afonin S, Ulrich AS, Komarov IV. An optimized protocol for the multigram synthesis of 3-(trifluoromethyl)bicyclo[1.1.1]pent-1-ylglycine (CF3-Bpg). J Fluor Chem 2010. [DOI: 10.1016/j.jfluchem.2009.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
13
|
Tuin AW, Palachanis DK, Buizert A, Grotenbreg GM, Spalburg E, de Neeling AJ, Mars-Groenendijk RH, Noort D, van der Marel GA, Overkleeft HS, Overhand M. Synthesis and Biological Evaluation of Novel Gramicidin S Analogues. European J Org Chem 2009. [DOI: 10.1002/ejoc.200900460] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
14
|
Wadhwani P, Bürck J, Strandberg E, Mink C, Afonin S, Ulrich AS. Using a sterically restrictive amino acid as a 19F NMR label to monitor and to control peptide aggregation in membranes. J Am Chem Soc 2009; 130:16515-7. [PMID: 19554688 DOI: 10.1021/ja804928q] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Parvesh Wadhwani
- Karlsruhe Institute of Technology, Institute for Biological Interfaces (IBG-2), Forschungszentrum Karlsruhe, POB 3640, 76021 Karlsruhe, Germany
| | | | | | | | | | | |
Collapse
|
15
|
Grage SL, Dürr UHN, Afonin S, Mikhailiuk PK, Komarov IV, Ulrich AS. Solid state 19F NMR parameters of fluorine-labeled amino acids. Part II: aliphatic substituents. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 191:16-23. [PMID: 18155628 DOI: 10.1016/j.jmr.2007.11.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 10/30/2007] [Accepted: 11/21/2007] [Indexed: 05/25/2023]
Abstract
A representative set of amino acids with aliphatic 19F-labels has been characterized here, following up our previous compilation of NMR parameters for single 19F-substituents on aromatic side chains. Their isotropic chemical shifts, chemical shift tensor parameters, intra-molecular 19F dipole-dipole couplings and temperature-dependent T1 and T2 relaxation times were determined by solid state NMR on twelve polycrystalline amino acid samples, and the corresponding isotropic 19F chemical shifts and scalar couplings were obtained in solution. Of particular interest are amino acids carrying a trifluoromethyl-group, because not only the 19F chemical shift but also the intra-CF3 homonuclear dipolar coupling can be used for structural studies of 19F-labeled peptides and proteins. The CF3-groups are further compared with CH2F-, CD2F-, and CD3-groups, using both 19F and 2H NMR to describe their motional behavior and to examine the respective linebroadening effects of the protonated and deuterated neighbors. We have also characterized two unnatural amino acids in which a CF3-label is rigidly connected to the backbone by a phenyl or bicyclopentyl moiety, and which are particularly well suited for structure analysis of membrane-bound polypeptides. The 19F NMR parameters of the polycrystalline amino acids are compared with data from the correspondingly labeled side chains in synthetic peptides.
Collapse
Affiliation(s)
- Stephan L Grage
- Forschungszentrum Karlsruhe, Institute of Biological Interfaces, P.O.B. 3640, 76021 Karlsruhe, Germany
| | | | | | | | | | | |
Collapse
|
16
|
Dürr UHN, Grage SL, Witter R, Ulrich AS. Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: aromatic substituents. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 191:7-15. [PMID: 18155936 DOI: 10.1016/j.jmr.2007.11.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 10/30/2007] [Accepted: 11/21/2007] [Indexed: 05/25/2023]
Abstract
Structural parameters of peptides and proteins in biomembranes can be directly measured by solid state NMR of selectively labeled amino acids. The 19F nucleus is a promising label to overcome the low sensitivity of 2H, 13C or 15N, and to serve as a background-free reporter group in biological compounds. To make the advantages of solid state 19F NMR fully available for structural studies of polypeptides, we have systematically measured the chemical shift anisotropies and relaxation properties of the most relevant aromatic and aliphatic 19F-labeled amino acids. In this first part of two consecutive contributions, six different 19F-substituents on representative aromatic side chains were characterized as polycrystalline powders by static and MAS experiments. The data are also compared with results on the same amino acids incorporated in synthetic peptides. The spectra show a wide variety of lineshapes, from which the principal values of the CSA tensors were extracted. In addition, temperature-dependent T(1) and T(2) relaxation times were determined by 19F NMR in the solid state, and isotropic chemical shifts and scalar couplings were obtained in solution.
Collapse
Affiliation(s)
- Ulrich H N Dürr
- Max-Planck-Institute for Biophysical Chemistry, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | | | | | | |
Collapse
|
17
|
Witter R, Nozirov F, Sternberg U, Cross TA, Ulrich AS, Fu R. Solid-state 19F NMR spectroscopy reveals that Trp41 participates in the gating mechanism of the M2 proton channel of influenza A virus. J Am Chem Soc 2007; 130:918-24. [PMID: 18163621 DOI: 10.1021/ja0754305] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The integral membrane protein M2 of influenza A virus assembles as a tetrameric bundle to form a proton-conducting channel that is activated by low pH. The side chain of His37 in the transmembrane alpha-helix is known to play an important role in the pH activation of the proton channel. It has also been suggested that Trp41, which is located in an adjacent turn of the helix, forms part of the gating mechanism. Here, a synthetic 25-residue peptide containing the M2 transmembrane domain was labeled with 6F-Trp41 and studied in lipid membranes by solid-state 19F NMR. We monitored the pH-dependent differences in the 19F dipolar couplings and motionally narrowed chemical shift anisotropies of this 6F-Trp41 residue, and we discuss the pH activation mechanism of the H+ channel. At pH 8.0, the structural parameters implicate an inactivated state, while at pH 5.3 the tryptophan conformation represents the activated state. With the aid of COSMOS force field simulations, we have obtained new side-chain torsion angles for Trp41 in the inactivated state (chi1 = -100 degrees +/- 10 degrees , chi2 = +110 degrees +/- 10 degrees ), and we predict a most probable activated state with chi1 = -50 degrees +/- 10 degrees and chi2 = +115 degrees +/- 10 degrees . We have also validated the torsion angles of His37 in the inactivated state as chi1 = -175 degrees +/- 10 degrees and chi2 = -170 degrees +/- 10 degrees .
Collapse
Affiliation(s)
- Raiker Witter
- Forschungszentrum Karlsruhe, IBG, POB 3640, 76021 Karlsruhe, Germany
| | | | | | | | | | | |
Collapse
|
18
|
Berditsch M, Afonin S, Ulrich AS. The ability of Aneurinibacillus migulanus (Bacillus brevis) to produce the antibiotic gramicidin S is correlated with phenotype variation. Appl Environ Microbiol 2007; 73:6620-8. [PMID: 17720841 PMCID: PMC2075075 DOI: 10.1128/aem.00881-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phenotype instability of bacterial strains can cause significant problems in biotechnological applications, since industrially useful properties may be lost. Here we report such degenerative dissociation for Aneurinibacillus migulanus (formerly known as Bacillus brevis) an established producer of the antimicrobial peptide gramicidin S (GS). Phenotypic variations within and between various strains maintained in different culture collections are demonstrated. The type strain, ATCC 9999, consists of six colony morphology variants, R, RC, RP, RT, SC, and SP, which were isolated and characterized as pure cultures. Correlations between colony morphology, growth, GS production, spore formation, and resistance to their own antimicrobial peptide were established in this study. We found the original R form to be the best producer, followed by RC, RP, and RT, while SC and SP yielded no GS at all. Currently available ATCC 9999(T) contains only 2% of the original R producer and is dominated by the newly described phenotypes RC and RP. No original R form is detected in the nominally equivalent strain DSM 2895(T) (=ATCC 9999(T)), which grows only as SC and SP phenotypes and has thus completely lost its value as a peptide producer. Two other strains from the same collection, DSM 5668 and DSM 5759, contain the unproductive SC variant and the GS-producing RC form, respectively. We describe the growth and maintenance conditions that stabilize certain colony phenotypes and reduce the degree of degenerative dissociation, thus providing a recommendation for how to revert the nonproducing smooth phenotypes to the valuable GS-producing rough ones.
Collapse
Affiliation(s)
- Marina Berditsch
- University of Karlsruhe (TH), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
| | | | | |
Collapse
|