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Utilizing zeta potential measurements to study the effective charge, membrane partitioning, and membrane permeation of the lipopeptide surfactin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2306-12. [PMID: 24631665 DOI: 10.1016/j.bbamem.2014.02.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 02/21/2014] [Indexed: 11/24/2022]
Abstract
The effective charge of membrane-active molecules such as the fungicidal lipopeptide surfactin (SF) is a crucial property governing solubility, membrane partitioning, and membrane permeability. We present zeta potential measurements of liposomes to measure the effective charge as well as membrane partitioning of SF by utilizing what we call an equi-activity analysis of several series of samples with different lipid concentrations. We observe an effective charge of -1.0 for SF at pH8.5 and insignificantly lower at pH7.4, illustrating that the effective charge may deviate strongly from the nominal value (-2 for 1 Asp, 1 Glu). The apparent partition coefficient decreases from roughly 100 to 20/mM with increasing membrane content of SF in agreement with the literature. Finally, by comparing zeta potentials measured soon after the addition of peptide to liposomes with those measured after a heat treatment to induce transmembrane equilibration of SF, we quantified the asymmetry of partitioning between the outer and inner leaflets. At very low concentration, SF binds exclusively to the outer leaflet. The onset of partial translocation to the inner leaflet occurs at about 5mol-% SF in the membrane. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
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Gang HZ, Liu JF, Mu BZ. Molecular Dynamics Study of Surfactin Monolayer at the Air/Water Interface. J Phys Chem B 2011; 115:12770-7. [DOI: 10.1021/jp206350j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Hong-Ze Gang
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
| | - Jin-Feng Liu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
| | - Bo-Zhong Mu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
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Liu X, Ren B, Chen M, Wang H, Kokare CR, Zhou X, Wang J, Dai H, Song F, Liu M, Wang J, Wang S, Zhang L. Production and characterization of a group of bioemulsifiers from the marine Bacillus velezensis strain H3. Appl Microbiol Biotechnol 2010; 87:1881-93. [DOI: 10.1007/s00253-010-2653-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 04/01/2010] [Accepted: 04/27/2010] [Indexed: 10/19/2022]
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Zou A, Liu J, Garamus VM, Yang Y, Willumeit R, Mu B. Micellization Activity of the Natural Lipopeptide [Glu1, Asp5] Surfactin-C15 in Aqueous Solution. J Phys Chem B 2010; 114:2712-8. [DOI: 10.1021/jp908675s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aihua Zou
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
| | - Jing Liu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
| | - Vasil M. Garamus
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
| | - Ying Yang
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
| | - Regine Willumeit
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
| | - Bozhong Mu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, P.R. China, and GKSS Research Center, Max-Planck-Str.1, 21502 Geesthacht, Germany
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Nanoscale membrane activity of surfactins: Influence of geometry, charge and hydrophobicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2058-68. [DOI: 10.1016/j.bbamem.2008.03.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 03/21/2008] [Accepted: 03/31/2008] [Indexed: 11/18/2022]
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Abstract
Antimicrobial peptides are ancient components of the innate immune system and have been isolated from organisms spanning the phylogenetic spectrum. Over an evolutionary time span, these peptides have retained potency, in the face of highly mutable target microorganisms. This fact suggests important coevolutionary influences in the host-pathogen relationship. Despite their diverse origins, the majority of antimicrobial peptides have common biophysical parameters that are likely essential for activity, including small size, cationicity, and amphipathicity. Although more than 900 different antimicrobial peptides have been characterized, most can be grouped as belonging to one of three structural classes: (1) linear, often of alpha-helical propensity; (2) cysteine stabilized, most commonly conforming to beta-sheet structure; and (3) those with one or more predominant amino acid residues, but variable in structure. Interestingly, these biophysical and structural features are retained in ribosomally as well as nonribosomally synthesized peptides. Therefore, it appears that a relatively limited set of physicochemical features is required for antimicrobial peptide efficacy against a broad spectrum of microbial pathogens. During the past several years, a number of themes have emerged within the field of antimicrobial peptide immunobiology. One developing area expands upon known microbicidal mechanisms of antimicrobial peptides to include targets beyond the plasma membrane. Examples include antimicrobial peptide activity involving structures such as extracellular polysaccharide and cell wall components, as well as the identification of an increasing number of intracellular targets. Additional areas of interest include an expanding recognition of antimicrobial peptide multifunctionality, and the identification of large antimicrobial proteins, and antimicrobial peptide or protein fragments derived thereof. The following discussion highlights such recent developments in antimicrobial peptide immunobiology, with an emphasis on the biophysical aspects of host-defense polypeptide action and mechanisms of microbial resistance.
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Affiliation(s)
- Nannette Y Yount
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90509, USA
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7
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Mikhonin AV, Bykov SV, Myshakina NS, Asher SA. Peptide Secondary Structure Folding Reaction Coordinate: Correlation between UV Raman Amide III Frequency, Ψ Ramachandran Angle, and Hydrogen Bonding. J Phys Chem B 2006; 110:1928-43. [PMID: 16471764 DOI: 10.1021/jp054593h] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We used UV resonance Raman (UVRR) spectroscopy to quantitatively correlate the peptide bond AmIII3 frequency to its Psi Ramachandran angle and to the number and types of amide hydrogen bonds at different temperatures. This information allows us to develop a family of relationships to directly estimate the Psi Ramachandran angle from measured UVRR AmIII3 frequencies for peptide bonds (PBs) with known hydrogen bonding (HB). These relationships ignore the more modest Phi Ramachandran angle dependence and allow determination of the Psi angle with a standard error of +/-8 degrees , if the HB state of a PB is known. This is normally the case if a known secondary structure motif is studied. Further, if the HB state of a PB in water is unknown, the extreme alterations in such a state could additionally bias the Psi angle by +/-6 degrees . The resulting ability to measure Psi spectroscopically will enable new incisive protein conformational studies, especially in the field of protein folding. This is because any attempt to understand reaction mechanisms requires elucidation of the relevant reaction coordinate(s). The Psi angle is precisely the reaction coordinate that determines secondary structure changes. As shown elsewhere (Mikhonin et al. J. Am. Chem. Soc. 2005, 127, 7712), this correlation can be used to determine portions of the energy landscape along the Psi reaction coordinate.
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Affiliation(s)
- Aleksandr V Mikhonin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Heerklotz H, Wieprecht T, Seelig J. Membrane Perturbation by the Lipopeptide Surfactin and Detergents as Studied by Deuterium NMR. J Phys Chem B 2004. [DOI: 10.1021/jp0371938] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Heiko Heerklotz
- Biozentrum der Universität Basel, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
| | - Torsten Wieprecht
- Biozentrum der Universität Basel, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
| | - Joachim Seelig
- Biozentrum der Universität Basel, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland
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9
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Xu G, Martinez JS, Groves JT, Butler A. Membrane affinity of the amphiphilic marinobactin siderophores. J Am Chem Soc 2002; 124:13408-15. [PMID: 12418892 DOI: 10.1021/ja026768w] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Marinobactins are a class of newly discovered marine bacterial siderophores with a unique amphiphilic structure, suggesting that their functions relate to interactions with cell membranes. Here we use small and large unilamellar L-alpha-dimyristoylphosphatidylcholine vesicles (SUVs and LUVs) as model membranes to examine the thermodynamics and kinetics of the membrane binding of marinobactins, particularly marinobactin E (apo-M(E)) and its iron(III) complex, Fe-M(E). Siderophore-membrane interactions are characterized by NMR line broadening, stopped-flow spectrophotometry, fluorescence quenching, and ultracentrifugation. It is determined that apo-M(E) has a strong affinity for lipid membranes with molar fraction partition coefficients K(x)()(apo)(-)(M)E = 6.3 x 10(5) for SUVs and 3.6 x 10(5) for LUVs. This membrane association is shown to cause only a 2-fold decrease in the rate of iron(III) binding by apo-M(E). However, upon the formation of the iron(III) complex Fe-M(E), the membrane affinity of the siderophore decreased substantially (K(x)()(Fe)(-)(M)E = 1.3 x 10(4) for SUVs and 9.6 x 10(3) for LUVs). The kinetics of membrane binding and dissociation by Fe-M(E) were also determined (k(on)(Fe)(-)(M)E = 1.01 M(-)(1) s(-)(1); k(off)(Fe)(-)(M)E = 4.4 x 10(-)(3) s(-)(1)). The suite of marinobactins with different fatty acid chain lengths and degrees of chain unsaturation showed a range of membrane affinities (5.8 x 10(3) to 36 M(-)(1)). The affinity that marinobactins exhibit for membranes and the changes observed upon iron binding could provide unique biological advantages in a receptor-assisted iron acquisition process in which loss of the iron-free siderophore by diffusion is limited by the strong association with the lipid phase.
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Affiliation(s)
- Guofeng Xu
- Department of Chemistry, Princeton University, New Jersey 08544, USA
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Symmank H, Franke P, Saenger W, Bernhard F. Modification of biologically active peptides: production of a novel lipohexapeptide after engineering of Bacillus subtilis surfactin synthetase. Protein Eng Des Sel 2002; 15:913-21. [PMID: 12538911 DOI: 10.1093/protein/15.11.913] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Bacillus subtilis strain ATCC 21332 produces the lipoheptapeptide surfactin, a highly potent biosurfactant synthesized by a large multimodular peptide synthetase. We report the genetic engineering of the surfactin biosynthesis resulting in the production of a novel lipohexapeptide with altered antimicrobial activities. A combination of in vitro and in vivo recombination approaches was used to construct a modified peptide synthetase by eliminating a large internal region of the enzyme containing a complete amino acid incorporating module. The remaining modules adjacent to the deletion were recombined at different highly conserved sequence motifs characteristic of amino acid incorporating modules of peptide synthetases. The primary goal of this work was to identify permissive fusion sites suitable for the engineering of peptide synthetase genes by genetic recombination. Analysis of the rearranged enzymes after purification from B. subtilis and from the heterologous host Escherichia coli revealed that the selection of the recombination site is of crucial importance for a successful engineering. Only the recombination at a specific HHII x DGVS sequence motif resulted in an active peptide synthetase. The expected lipohexapeptide was produced in vivo and first evidence of a reduced toxicity against erythrocytes and an enhanced lysis of Bacillus licheniformis cells was shown.
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Affiliation(s)
- Hanka Symmank
- Institut für Kristallographie, Takustrasse 6 , Freie Universität Berlin, D-14195 Berlin, Germany
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11
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Abstract
Surfactin is a bacterial lipopeptide with powerful surfactant-like properties. High-sensitivity isothermal titration calorimetry was used to study the self association and membrane partitioning of surfactin. The critical micellar concentration (CMC), was 7.5 microM, the heat of micellization was endothermic with DeltaH(w-->m)(Su) = +4.0 kcal/mol, and the free energy of micellization DeltaG(O,w-->m)(Su) = -9.3 kcal/mol (25 degrees C; 100 mM NaCl; 10 mM TRIS, 1 mM EDTA; pH 8.5). The specific heat capacity of micellization was deduced from temperature dependence of DeltaH(w-->m)(Su) as DeltaC(w-->m)(P) = -250 +/- 10 cal/(mol.K). The data can be explained by combining the hydrophobicity of the fatty acyl chain with that of the hydrophobic amino acids. The membrane partition equilibrium was studied using small (30 nm) and large (100 nm) unilamellar POPC vesicles. At 25 degrees C, the partition coefficient, K, was (2.2 +/- 0.2) x 10(4) M(-1) for large vesicles leading to a free energy of DeltaG(O, w-->b)(Su) = -8.3 kcal/mol. The partition enthalpy was again endothermic, with DeltaH(w-->b)(Su) = 9 +/- 1 kcal/mol. The strong preference of surfactin for micelle formation over membrane insertion explains the high membrane-destabilizing activity of the peptide. For surfactin and a variety of non-ionic detergents, the surfactant-to-lipid ratio, inducing membrane solubilization, R(sat)(b), can be predicted by the simple relationship R(sat)(b) approximately K. CMC.
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Affiliation(s)
- H Heerklotz
- Department of Biophysical Chemistry, Biocenter of the University of Basel, CH-4056 Basel, Switzerland
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12
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Grangemard I, Peypoux F, Wallach J, Das BC, Labbé H, Caille A, Genest M, Maget-Dana R, Ptak M, Bonmatin JM. Lipopeptides with improved properties: structure by NMR, purification by HPLC and structure-activity relationships of new isoleucyl-rich surfactins. J Pept Sci 1997; 3:145-54. [PMID: 9230480 DOI: 10.1002/(sici)1099-1387(199703)3:2<145::aid-psc96>3.0.co;2-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The biosynthesis of bacterial isoleucyl-rich surfactins was controlled by supplementation of L-isoleucine to the culture medium. Two new variants, the [Ile4,7]- and [Ile2,4,7]surfactins, were thus produced by Bacillus subtilis and their separation was achieved by reverse-phase HPLC. Amino acids of the heptapeptide moiety were analysed by chemical methods, and the lipid moiety was identified by beta-hydroxy anteiso pentadecanoic acid by combined GC/MS. Sequences were established on the basis of two-dimensional NMR data. Because conformational parameters issuing from NMR spectra suggested that the cyclic backbone fold was globally conserved in the new variants, structure-activity relationships were discussed in details on the basis of the three-dimensional model of surfactin in solution. Indeed, both variants have increased surface properties compared with that of surfactin, and this improvement is assigned to an increase of the hydrophobicity of the apolar domain favouring micellization. Furthermore, the additional Leu-to-Ile substitution at position 2 in the [Ile2,4,7]surfactin leads to a substantial increase of its affinity for calcium, when compared with that of [Ile4,7]surfactin or surfactin. This effect is assigned, from the model, to an increase in the accessibility of the acidic side chains constituting the calcium binding site. Thus, the propensities of such active lipopeptides for both hydrophobic and electrostatic interactions were improved, further substantiating that they can be rationally designed.
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Affiliation(s)
- I Grangemard
- Laboratoire de Biochimie Analytique et Synthèse Bioorganique, Université Claude Bernard Lyon, France
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Bonmatin JM, Labb� H, Grangemard I, Peypoux F, Maget-Dana R, Ptak M, Michel G. Production, isolation and characterization of [Leu4]- and [Ile4]surfactins from Bacillus subtilis. ACTA ACUST UNITED AC 1995. [DOI: 10.1007/bf00122922] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Ishigami Y, Osman M, Nakahara H, Sano Y, Ishiguro R, Matsumoto M. Significance of β-sheet formation for micellization and surface adsorption of surfactin. Colloids Surf B Biointerfaces 1995. [DOI: 10.1016/0927-7765(94)01183-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Cornet B, Bonmatin JM, Hetru C, Hoffmann JA, Ptak M, Vovelle F. Refined three-dimensional solution structure of insect defensin A. Structure 1995; 3:435-48. [PMID: 7663941 DOI: 10.1016/s0969-2126(01)00177-0] [Citation(s) in RCA: 237] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Insect defensin A is a basic 4 kDa protein secreted by Phormia terranovae larvae in response to bacterial challenges or injuries. Previous biological tests suggest that the bacterial cytoplasmic membrane is the target of defensin A. The structural study of this protein is the first step towards establishing a structure-activity relationship and forms the basis for understanding its antibiotic activity at the molecular level. RESULTS We describe a refined model of the three-dimensional structure of defensin A derived from an extensive analysis of 786 inter-proton nuclear Overhauser effects. The backbone fold involves an N-terminal loop and an alpha-helical fragment followed by an antiparallel beta-structure. The helix and the beta-structure are connected by two of the three disulphide bridges present in defensin A, forming a so-called 'cysteine-stabilized alpha beta' (CS alpha beta) motif. The N-terminal loop, which is locally well defined, can occupy different positions with respect to the other moieties of the molecule. CONCLUSIONS The CS alpha beta motif, which forms the core of the defensin A structure, appears to be a common organization for several families of small proteins with toxic properties. The distribution of amino acid side chains in the protein structure creates several hydrophobic or hydrophilic patches. This leads us to propose that the initial step in the action of positively charged defensin A molecules with cytoplasmic membranes may involve interactions with acidic phospholipids.
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Affiliation(s)
- B Cornet
- Centre de Biophysique Moléculaire (CNRS), Orléans, France
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16
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Maget-Dana R, Bonmatin JM, Hetru C, Ptak M, Maurizot JC. The secondary structure of the insect defensin A depends on its environment. A circular dichroism study. Biochimie 1995; 77:240-4. [PMID: 8589051 DOI: 10.1016/0300-9084(96)88130-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Defensin A is an inducible antibacterial protein isolated from the larvae of Phormia terranovae. The conformation of defensin A has been previously determined by two-dimensional 1H-NMR for concentrations in the range of 4-8 mM in water (Bonmatin JM et al (1992) J Biomol NMR 2, 235-256). CD spectroscopic data of defensin A at lower concentrations (10(-5) to 10(-3) M) are reported herein. The ellipticity in the 200-240 nm wavelength range for various solvents varies as follows: acetonitrile < water < methanol < HFIP. The magnitude of theta 222 is strongly dependent on defensin concentration in a buffer solution, suggesting an aggregation process. The helical content of defensin A is maximum at a pH value range (7.5-8) for which the optimum antibacterial activity was observed (Cociancich S et al (1993) J Biol Chem 268, 19239-19245).
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Affiliation(s)
- R Maget-Dana
- Centre de Biophysique Moléculaire (CNRS), Université d'Orléans, France
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17
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Dynamic transition of ?-helix to ?-sheet structure in linear surfactin correlating to critical micelle concentration. Biotechnol Lett 1994. [DOI: 10.1007/bf00128624] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Peypoux F, Bonmatin JM, Labbe H, Grangemard I, Das BC, Ptak M, Wallach J, Michel G. [Ala4]surfactin, a novel isoform from Bacillus subtilis studied by mass and NMR spectroscopies. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 224:89-96. [PMID: 8076655 DOI: 10.1111/j.1432-1033.1994.tb19998.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
When Bacillus subtilis S 499 was grown on a culture medium containing L-alanine as nitrogen source, a mixture of surfactins was obtained. Suitable chromatographic conditions allowed the separation of isoforms. Among these compounds, a new variant of surfactin was isolated and its structure was established by chemical and spectrometric methods, especially by NMR spectrometry. It contains a peptide sequence which differs from that of standard surfactin by the replacement of the L-valine residue by L-alanine residue in position 4. The folding mode of [Ala4]surfactin as deduced from NMR results was compared with that of standard surfactin and the structure/properties relationship issuing from the study of this new isoform is discussed.
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Affiliation(s)
- F Peypoux
- Laboratoire de Biochimie Microbienne, Université Claude Bernard Lyon 1, France
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Bonmatin JM, Genest M, Labbé H, Ptak M. Solution three-dimensional structure of surfactin: a cyclic lipopeptide studied by 1H-NMR, distance geometry, and molecular dynamics. Biopolymers 1994; 34:975-86. [PMID: 8054476 DOI: 10.1002/bip.360340716] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The solution three-dimensional structure of the protonated [Leu7]-surfactin, an heptapeptide extracted from Bacillus subtilis, has been determined from two-dimensional 1H-nmr performed in 2H6-dimethylsulfoxide and combined with molecular modeling. Experimental data included 9 coupling constants, 61 nuclear Overhauser effect derived distances, NH temperature coefficients, and 13C relaxation times. Two distance geometry (DISMAN) protocols converged toward models of the structure and the best of them were refined by restrained and unrestrained molecular dynamics (GROMOS). Two structures in accord with the set of experimental constraints are presented. Both are characterized by a "horse saddle" topology for ring atoms on which are attached the two polar Glu and Asp side chains showing an orientation clearly opposite to that of the C11-13 aliphatic chain. Amphipathic and surface properties of surfactin are certainly related to the existence of such minor polar and a major hydrophobic domains. The particular "claw" configuration of acidic residues observed in surfactin gives important clues for the understanding of its cation binding and transporting ability.
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Affiliation(s)
- J M Bonmatin
- Laboratoire de Biophysique Moléculaire (CNRS), Orléans, France
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20
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Petit MC, Sodano P, Marion D, Ptak M. Two-dimensional 1H-NMR studies of maize lipid-transfer protein. Sequence-specific assignment and secondary structure. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 222:1047-54. [PMID: 8026483 DOI: 10.1111/j.1432-1033.1994.tb18957.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY) and NOE spectroscopy (NOESY) experiments have been used to assign sequentially the 1H 500-MHz NMR spectra of a non-specific (ns) lipid-transfer protein extracted from maize seeds. The spin-system identification and sequential assignment were combined with secondary-structure determination to identify most of the proton resonances of this 93-residue protein. From the sequential connectivities it was established that the secondary structure mainly involved four helical fragments: H1, H2, H3 and H4. This secondary structure was compared with that of wheat ns-lipid-transfer protein recently determined. The four helices are located in nearly the same regions, but helix H4 is appreciably longer in the maize protein than in the wheat protein. Comparison of the transfer activities reveals that the maize protein is more efficient than the wheat ns-lipid-transfer protein and that this difference is probably due to the affinity of the lipid for the binding site and not to the interfacial activation, i.e. adsorption of the ns-lipid-transfer protein to the membrane. From these results, it is suggested that helix H4 is a part of the lipid-binding site or contributes to the folding of this site. The present data define the basis for a further modelling of the three-dimensional structure of the maize ns-lipid-transfer protein which will be compared with that of the wheat ns-lipid-transfer protein in order to establish structure/activity relationships for this class of carriers by using natural ns-lipid-transfer protein mutants.
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Affiliation(s)
- M C Petit
- Centre de Biophysique Moléculaire (CNRS), Orléans, France
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