1
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Masoudi Y, van Rensburg W, Barnard-Jenkins B, Rautenbach M. The Influence of Cellulose-Type Formulants on Anti- Candida Activity of the Tyrocidines. Antibiotics (Basel) 2021; 10:antibiotics10050597. [PMID: 34069885 PMCID: PMC8157355 DOI: 10.3390/antibiotics10050597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 11/16/2022] Open
Abstract
Candida species are highly adaptable to environmental changes with their phenotypic flexibility allowing for the evasion of most host defence mechanisms. Moreover, increasing resistance of human pathogenic Candida strains has been reported against all four classes of available antifungal drugs, which highlights the need for combinational therapies. Tyrocidines are cyclic antimicrobial peptides that have shown synergistic activity with antifungal drugs such as caspofungin and amphotericin B. However, these cyclodecapeptides have haemolytic activity and cytotoxicity, but they have been used for decades in the clinic for topical applications. The tyrocidines tend to form higher-order structures in aqueous solutions and excessive aggregation can result in variable or diminished activity. Previous studies have shown that the tyrocidines prefer ordered association to celluloses. Therefore, a formulation with soluble cellulose was used to control the oligomer stability and size, thereby increasing the activity against Candida spp. Of the formulants tested, it was found that commercial hydroxy-propyl-methyl cellulose, E10M, yielded the best results with increased stability, increased anti-Candida activity, and improved selectivity. This formulation holds promise in topical applications against Candida spp. infections.
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2
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Rautenbach M, Kumar V, Vosloo JA, Masoudi Y, van Wyk RJ, Stander MA. Oligomerisation of tryptocidine C, a Trp-rich cyclodecapeptide from the antimicrobial tyrothricin complex. Biochimie 2020; 181:123-133. [PMID: 33333170 DOI: 10.1016/j.biochi.2020.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/17/2020] [Accepted: 12/12/2020] [Indexed: 01/07/2023]
Abstract
Tryptocidine C (TpcC, cyclo[D-Phe1-Pro2-Trp3-D-Trp4-Asn5-Gln6-Trp7-Val8-Orn9-Leu10]) is a broad-spectrum antimicrobial peptide in the tyrothricin complex produced by a soil bacterium, Brevibacillus parabrevis. Electrospray mass spectrometric studies reveal the oligomerisation of TpcC into dimers and higher oligomers, analogous to tyrocidine C (TrcC, Trp7 replaced by Tyr7). Ion mobility mass spectrometry (IMMS) further confirms the formation of stable peptide dimers and tetramers with diameters of 2.7 nm and 3.3 nm, respectively, calculated from collisional cross section (CCS). Molecular dynamic simulations and docking studies support the formation of amphipathic dimers, with a diameter of 2.5 ± 0.07 nm calculated from low energy model CCS. Circular dichroism and IMMS studies point towards dynamic hydrogen-bonded conformational changes up to 28-33 μM after which the structures become more static (or in equilibrium). Fluorescence studies indicate aromatic stacking of Trp residues with a CMC of 18 μM in aqueous solutions. The concentration and time dependent interaction of Trp in oligomers indicate cooperativity in the TpcC oligomerisation that leads to the formation of higher order microscopic structures. Scanning electron microscopy studies unequivocally shows that TpcC forms nanospheres with a mean diameter of 25 nm. Repeated smaller oligomeric units, possibly dimers and tetramers, self-assemble to form these nanospheres.
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Affiliation(s)
- Marina Rautenbach
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa.
| | - Vikas Kumar
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa.
| | - J Arnold Vosloo
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Yasamin Masoudi
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Rosalind J van Wyk
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Marietjie A Stander
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa; LC-MS Unit of the Central Analytical Facility, Stellenbosch University, Stellenbosch, South Africa
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3
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Juhl DW, van Rensburg W, Bossis X, Vosloo JA, Rautenbach M, Bechinger B. Tyrocidine A interactions with saccharides investigated by CD and NMR spectroscopies. J Pept Sci 2019; 25:e3163. [PMID: 30884009 DOI: 10.1002/psc.3163] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/10/2019] [Accepted: 02/12/2019] [Indexed: 01/23/2023]
Abstract
Tyrocidines are a family of cyclic decapeptides produced by the soil bacterium, Brevibacillus parabrevis. These antibiotic peptides can be used to prevent infections in agriculture and food industry but also to prepare antimicrobial lozenges, creams, and dressings for medical applications. It has been observed that the tyrocidines interact with saccharides such as cellulose from their soil environment, as well as sugars in culture media and glycans in fungal cell walls. Here, we investigated the interactions of tyrocidines with glucose, sucrose, and cellotetraose (as cellulose model) in a quantitative fashion utilising CD and NMR spectroscopy. The CD and NMR spectra of tyrocidine A (TrcA) were analysed as a function of solvent composition, and the spectral properties agree with the formation of oligomeric structures that are governed by β-sheet secondary structures once the acetonitrile content of the solvent is increased. Saccharides seem to also induce TrcA spectral changes reverting those induced by organic solvents. The CD spectral changes of TrcA in the presence of glucose agree with new ordered H-bonding, possibly β-sheet structures. The amides involved in intramolecular H-bonding remained largely unaffected by the environmental changes. In contrast, amides exposed to the exterior and/or involved in TrcA intermolecular association show the largest 1 H chemical shift changes. CD and NMR spectroscopic investigations correlated well with TrcA-glucose interactions characterized by a dissociation constant around 200 μM. Interestingly, the association of cellotetraose corresponds closely to the additive effect from four glucose moieties, while a much higher dissociation constant was observed for sucrose. Similar trends to TrcA for binding to the three saccharides were observed for the analogous tyrocidines, tyrocidine B, and tyrocidine C. These results therefore indicate that the tyrocidine interactions with the glucose monosaccharide unit are fairly specific and reversible.
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Affiliation(s)
| | - Wilma van Rensburg
- BIOPEP Peptide Group, Department of Biochemistry, University of Stellenbosch, Matieland, South Africa
| | | | - J Arnold Vosloo
- BIOPEP Peptide Group, Department of Biochemistry, University of Stellenbosch, Matieland, South Africa
| | - Marina Rautenbach
- BIOPEP Peptide Group, Department of Biochemistry, University of Stellenbosch, Matieland, South Africa
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4
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Loll PJ, Upton EC, Nahoum V, Economou NJ, Cocklin S. The high resolution structure of tyrocidine A reveals an amphipathic dimer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1199-207. [PMID: 24530898 DOI: 10.1016/j.bbamem.2014.01.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/20/2014] [Accepted: 01/27/2014] [Indexed: 11/28/2022]
Abstract
Tyrocidine A, one of the first antibiotics ever to be discovered, is a cyclic decapeptide that binds to membranes of target bacteria, disrupting their integrity. It is active against a broad spectrum of Gram-positive organisms, and has recently engendered interest as a potential scaffold for the development of new drugs to combat antibiotic-resistant pathogens. We present here the X-ray crystal structure of tyrocidine A at a resolution of 0.95Å. The structure reveals that tyrocidine forms an intimate and highly amphipathic homodimer made up of four beta strands that associate into a single, highly curved antiparallel beta sheet. We used surface plasmon resonance and potassium efflux assays to demonstrate that tyrocidine binds tightly to mimetics of bacterial membranes with an apparent dissociation constant (K(D)) of 10 μM, and efficiently permeabilizes bacterial cells at concentrations equal to and below the K(D). Using variant forms of tyrocidine in which the fluorescent probe p-cyano-phenylalanine had been inserted on either the polar or apolar face of the molecule, we performed fluorescence quenching experiments, using both water-soluble and membrane-embedded quenchers. The quenching results, together with the structure, strongly support a membrane association model in which the convex, apolar face of tyrocidine's beta sheet is oriented toward the membrane interior, while the concave, polar face is presented to the aqueous phase.
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Affiliation(s)
- Patrick J Loll
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
| | - Elizabeth C Upton
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Virginie Nahoum
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Nicoleta J Economou
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Simon Cocklin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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5
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Munyuki G, Jackson GE, Venter GA, Kövér KE, Szilágyi L, Rautenbach M, Spathelf BM, Bhattacharya B, van der Spoel D. β-Sheet Structures and Dimer Models of the Two Major Tyrocidines, Antimicrobial Peptides from Bacillus aneurinolyticus. Biochemistry 2013; 52:7798-806. [DOI: 10.1021/bi401363m] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gadzikano Munyuki
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-751 24 Uppsala, Sweden
| | - Graham E. Jackson
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
| | - Gerhard A. Venter
- Department
of Chemistry, University of Cape Town, P Bag X3, Rondebosch, Cape Town, South Africa 7701
| | - Katalin E. Kövér
- Department
of Chemistry, University of Debrecen, H-4010 Debrecen, Egyetem tér 1, Pf. 20, Hungary
| | - László Szilágyi
- Department
of Chemistry, University of Debrecen, H-4010 Debrecen, Egyetem tér 1, Pf. 20, Hungary
| | - Marina Rautenbach
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - Barbara M. Spathelf
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - Bhaswati Bhattacharya
- BIOPEP
Peptide group, Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa 7600
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-751 24 Uppsala, Sweden
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6
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Enck S, Kopp F, Marahiel MA, Geyer A. The reversible macrocyclization of Tyrocidine A aldehyde: a hemiaminal reminiscent of the tetrahedral intermediate of macrolactamization. Org Biomol Chem 2009; 8:559-63. [PMID: 20090972 DOI: 10.1039/b917549k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In spite of the important role of peptide macrocyclizations for the generation of conformationally constrained biological ligands, our knowledge of factors that determine the inclination of a substrate to cyclize is low. Therefore, methods that give access to the thermodynamic characterization of these processes are desirable. In this work, we present the isosteric substitution of the amide ligation site of a cyclopeptide by an imine. Applied to the decapeptide antibiotic Tyrocidine A (TycA), the reversible cyclization of the linear aldehyde TycA-CHO resulted in the unexpectedly stable hemiaminal Psi[CH(OH)NH]-TycA, which is equivalent to the tetrahedral intermediate of macrolactamization, and which is observed for the first time in a peptidic structure. On the basis of NMR spectroscopy and molecular modeling, we discuss the observed high stereoselectivity of hemiaminal formation, as well as its reluctance to be dehydrated to the imine. As required for thermodynamic analysis, it is possible to establish a pH- and temperature-dependent cyclization equilibrium, which allows determination of the entropy loss of the peptide chain, and quantification of the extent of preorientation of the cyclization precursor.
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Affiliation(s)
- Sebastian Enck
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
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7
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Spathelf BM, Rautenbach M. Anti-listerial activity and structure–activity relationships of the six major tyrocidines, cyclic decapeptides from Bacillus aneurinolyticus. Bioorg Med Chem 2009; 17:5541-8. [DOI: 10.1016/j.bmc.2009.06.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 06/08/2009] [Accepted: 06/14/2009] [Indexed: 10/20/2022]
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8
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Laungani AC, Slattery JM, Krossing I, Breit B. Supramolecular bidentate ligands by metal-directed in situ formation of antiparallel beta-sheet structures and application in asymmetric catalysis. Chemistry 2008; 14:4488-502. [PMID: 18449870 DOI: 10.1002/chem.200800359] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The principles of protein structure design, molecular recognition, and supramolecular and combinatorial chemistry have been applied to develop a convergent metal-ion-assisted self-assembly approach that is a very simple and effective method for the de novo design and the construction of topologically predetermined antiparallel beta-sheet structures and self-assembled catalysts. A new concept of in situ generation of bidentate P-ligands for transition-metal catalysis, in which two complementary, monodentate, peptide-based ligands are brought together by employing peptide secondary structure motif as constructing tool to direct the self-assembly process, is achieved through formation of stable beta-sheet motifs and subsequent control of selectivity. The supramolecular structures were studied by (1)H, (31)P, and (13)C NMR spectroscopy, ESI mass spectrometry, X-ray structure analysis, and theoretical calculations. Our initial catalysis results confirm the close relationship between the self-assembled sheet conformations and the catalytic activity of these metallopeptides in the asymmetric rhodium-catalyzed hydroformylation. Good catalyst activity and moderate enantioselectivity were observed for the selected combination of catalyst and substrate, but most importantly the concept of this new methodology was successfully proven. This work presents a perspective interface between protein design and supramolecular catalysis for the design of beta-sheet mimetics and screening of libraries of self-organizing supramolecular catalysts.
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Affiliation(s)
- Andy C Laungani
- Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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9
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Samel SA, Schoenafinger G, Knappe TA, Marahiel MA, Essen LO. Structural and functional insights into a peptide bond-forming bidomain from a nonribosomal peptide synthetase. Structure 2007; 15:781-92. [PMID: 17637339 DOI: 10.1016/j.str.2007.05.008] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 05/15/2007] [Accepted: 05/16/2007] [Indexed: 11/29/2022]
Abstract
The crystal structure of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyrocidine synthetase TycC was determined at 1.8 A resolution. The bidomain structure reveals a V-shaped condensation domain, the canyon-like active site groove of which is associated with the preceding peptidyl carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming condensation (C) domain places the active sites approximately 50 A apart. Accordingly, this PCP-C structure represents a conformational state prior to peptide transfer from the donor-PCP to the acceptor-PCP domain, implying the existence of additional states of PCP-C domain interaction during catalysis. Additionally, PCP-C exerts a mode of cyclization activity that mimics peptide bond formation catalyzed by C domains. Based on mutational data and pK value analysis of active site residues, it is suggested that nonribosomal peptide bond formation depends on electrostatic interactions rather than on general acid/base catalysis.
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Affiliation(s)
- Stefan A Samel
- Department of Chemistry/Biochemistry, Philipps-Universität, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
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10
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Marques MA, Citron DM, Wang CC. Development of Tyrocidine A analogues with improved antibacterial activity. Bioorg Med Chem 2007; 15:6667-77. [PMID: 17728134 PMCID: PMC2706120 DOI: 10.1016/j.bmc.2007.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 07/05/2007] [Accepted: 08/07/2007] [Indexed: 11/25/2022]
Abstract
The development of new antibacterial therapeutic agents capable of halting microbial resistance is a chief pursuit in clinical medicine. Classes of antibiotics that target and destroy bacterial membranes are attractive due to the decreased likelihood that bacteria will be able to generate resistance to this mechanism. The amphipathic cyclic decapeptide, Tyrocidine A, is a model for this class of antibiotics. Tyrocidine A is composed of a hydrophobic and a hydrophilic face, allowing for insertion into bacterial membranes, creating porous channels and destroying membrane integrity. We have used a combination of molecular modeling and solid phase synthesis to prepare Tyrocidine A and analogues 1-8. The minimum inhibitory concentrations (MICs) of these compounds were determined for a host of gram positive species and E. coli as a representative gram negative bacterium. Analogues 2 and 5 demonstrated moderate 2- to 8-fold increases in antibacterial activity over the parent Tyrocidine A for a variety of pathogenic microbes (best MICs for E. coli 32 microg/mL and 2 microg/mL for most gram positives). Examination of the structure- activity relationship between the analogues demonstrated a preference for increased amphipathicity but did not show a clear preference for increasing hydrophilicity versus hydrophobicity in improving antibacterial activity. Of note, movement of positively charged lysine residues or neutral pentafluorophenyl residues to different positions within the cyclopeptide ring system demonstrated improvements in antibacterial activity.
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Affiliation(s)
- Michael A. Marques
- Department of Pharmacology and Department of Chemistry, University of Southern California, 1985 Zonal Ave, Los Angeles California 90089
| | - Diane M. Citron
- Microbial Research Lab, Los Angeles County, University of Southern California Medical Center, 1801 East Marengo Street 2G-24, Los Angeles, California 90033
| | - Clay C. Wang
- Department of Pharmacology and Department of Chemistry, University of Southern California, 1985 Zonal Ave, Los Angeles California 90089
- Corresponding Author: Clay C. Wang, Department of Pharmacology and Department of Chemistry, University of Southern California, 1985 Zonal Ave, Los Angeles, California 90089, Phone: (323) 442-1670, Fax: (323) 442-1365,
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11
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Abstract
Cyclic peptides are a rich source of biologically active compounds and are produced in nature by plants, bacteria, fungi, and lower sea animals. A high-throughput methodology has been developed for the combinatorial synthesis, screening, and identification of cyclic peptide natural product analogues with improved biological activities or useful new activities. The methodology was applied to generate a library of 1716 tyrocidine A analogues, which were screened for antibacterial activity in 96-well plates. The identity of the active peptides was determined by partial Edman degradation/mass spectrometry. This has resulted in the discovery of a series of tyrocidine analogues that have significantly improved therapeutic indices compared to the natural product. The availability of tyrocidine analogues with varying antibacterial activities has provided important insights into the structure-function relationship of tyrocidine A, which should help reveal its mechanism of action.
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Affiliation(s)
| | - Dehua Pei
- To whom all correspondence should be addressed at: Dehua Pei, Department of Chemistry, The Ohio State University, 100 West 18 Avenue, Columbus, OH 43210. Phone: 614−688−4068; Fax: 614−292−1532; E-mail:
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12
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Thayer DA, Yu HN, Galan MC, Wong CH. A general strategy toward S-linked glycopeptides. Angew Chem Int Ed Engl 2006; 44:4596-9. [PMID: 15991213 DOI: 10.1002/anie.200500090] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Desiree A Thayer
- Department of Chemistry and Skaggs Institute for Chemical Biology, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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13
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Thayer DA, Yu HN, Galan MC, Wong CH. A General Strategy toward S-Linked Glycopeptides. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200500090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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CLORE GM, GRONENBORN AM, MITCHINSON C, GREEN NM. 1H-NMR Studies on Nucleotide Binding to the Sarcoplasmic Reticulum Ca2+ ATPase. ACTA ACUST UNITED AC 2005. [DOI: 10.1111/j.1432-1033.1982.tb06940.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Robinson JA, Shankaramma SC, Jetter P, Kienzl U, Schwendener RA, Vrijbloed JW, Obrecht D. Properties and structure–activity studies of cyclic β-hairpin peptidomimetics based on the cationic antimicrobial peptide protegrin I. Bioorg Med Chem 2005; 13:2055-64. [PMID: 15727859 DOI: 10.1016/j.bmc.2005.01.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Accepted: 01/07/2005] [Indexed: 11/27/2022]
Abstract
The properties and structure-activity relationships (SAR) of a macrocyclic analogue of porcine protegrin I (PG-I) have been investigated. The lead compound, having the sequence cyclo-(-Leu-Arg-Leu-Lys-Lys-Arg-Arg-Trp-Lys-Tyr-Arg-Val-d-Pro-Pro-), shows antimicrobial activity against Gram-positive and -negative bacteria, but a much lower haemolytic activity and a much reduced ability to induce dye release from phosphatidylcholine/phosphatidylglycerol liposomes, when compared to PG-I. The enantiomeric form of the lead peptide shows comparable antimicrobial activity, a property shared with other cationic antimicrobial peptides acting on cell membranes. SAR studies involving the synthesis and biological profiling of over 100 single site substituted analogues, showed that the antimicrobial activity was tolerant to a large number of the substitutions tested. Some analogues showed slightly improved antimicrobial activities (2-4-fold lowering of MICs), whereas other substitutions caused large increases in haemolytic activity on human red blood cells.
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Affiliation(s)
- John A Robinson
- Institute of Organic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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16
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Qin C, Bu X, Wu X, Guo Z. A chemical approach to generate molecular diversity based on the scaffold of cyclic decapeptide antibiotic tyrocidine A. JOURNAL OF COMBINATORIAL CHEMISTRY 2003; 5:353-5. [PMID: 12857101 DOI: 10.1021/cc0300255] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chuanguang Qin
- Department of Chemistry and Biotechnology Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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17
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Kohli RM, Walsh CT, Burkart MD. Biomimetic synthesis and optimization of cyclic peptide antibiotics. Nature 2002; 418:658-61. [PMID: 12167866 DOI: 10.1038/nature00907] [Citation(s) in RCA: 223] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Molecules in nature are often brought to a bioactive conformation by ring formation (macrocyclization). A recurrent theme in the enzymatic synthesis of macrocyclic compounds by non-ribosomal and polyketide synthetases is the tethering of activated linear intermediates through thioester linkages to carrier proteins, in a natural analogy to solid-phase synthesis. A terminal thioesterase domain of the synthetase catalyses release from the tether and cyclization. Here we show that an isolated thioesterase can catalyse the cyclization of linear peptides immobilized on a solid-phase support modified with a biomimetic linker, offering the possibility of merging natural-product biosynthesis with combinatorial solid-phase chemistry. Starting from the cyclic decapeptide antibiotic tyrocidine A, this chemoenzymatic approach allows us to diversify the linear peptide both to probe the enzymology of the macrocyclizing enzyme, TycC thioesterase, and to create a library of cyclic peptide antibiotic products. We have used this method to reveal natural-product analogues of potential therapeutic utility; these compounds have an increased preference for bacterial over eukaryotic membranes and an improved spectrum of activity against some common bacterial pathogens.
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Affiliation(s)
- Rahul M Kohli
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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18
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Kondejewski LH, Lee DL, Jelokhani-Niaraki M, Farmer SW, Hancock REW, Hodges RS. Optimization of microbial specificity in cyclic peptides by modulation of hydrophobicity within a defined structural framework. J Biol Chem 2002; 277:67-74. [PMID: 11682479 DOI: 10.1074/jbc.m107825200] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the present study we have utilized the structural framework of the analog GS14K4 (cyclo(VKLd-KVd-YPL KVKLd-YP, where d denotes a d-amino acid)), to examine the role of hydrophobicity in microbial activity and specificity. The hydrophobicity of GS14K4 was systematically altered by residue replacements in the hydrophobic sites of the molecule to produce a series of analogs that were either less or more hydrophobic than the parent compound. Circular dichroism spectroscopy and reversed-phase high performance liquid chromatography analysis showed that the molecules were structurally similar and only differed in overall hydrophobicity. The hydrophobicity of GS14K4 was found to be the midpoint for hemolytic activity, with more hydrophobic analogs exhibiting increased hemolytic activity and less hydrophobic analogs showing decreased hemolytic activity. For antimicrobial activity there were differences between the hydrophobicity requirements against Gram-positive and Gram-negative microorganisms. The hydrophobicity of GS14K4 was sufficient for maximum activity against Gram-negative microorganisms and yeast, with no further increases in activity occurring with increasing hydrophobicity. With Gram-positive microorganisms significant increases in activity with increasing hydrophobicity were seen in three of the six microorganisms tested. A therapeutic index (calculated as a measure of specificity of the peptides for the microorganisms over human erythrocytes) served to define the boundaries of a therapeutic window within which lay the optimum peptide hydrophobicity for each microorganism. The therapeutic window was found to be at a lower hydrophobicity level for Gram-negative microorganisms than for Gram-positive microorganisms, although the limits were more variable for the latter. Our results show that the balance between activity and specificity in the present cyclic peptides can be optimized for each microorganism by systematic modulation of hydrophobicity.
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Affiliation(s)
- Leslie H Kondejewski
- Protein Engineering Network of Centres of Excellence, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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19
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Seio K, Wada T, Sakamoto K, Yokoyama S, Sekine M. Chemical Synthesis and Conformational Properties of a New Cyclouridylic Acid Having an Ethylene Bridge between the Uracil 5-Position and 5‘-Phosphate Group. J Org Chem 1996. [DOI: 10.1021/jo951756x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kohji Seio
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 226, Japan, and Department of Biophysics and Biochemistry, The University of Tokyo, Hongo, Bunkyoku, Tokyo 113, Japan
| | - Takeshi Wada
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 226, Japan, and Department of Biophysics and Biochemistry, The University of Tokyo, Hongo, Bunkyoku, Tokyo 113, Japan
| | - Kensaku Sakamoto
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 226, Japan, and Department of Biophysics and Biochemistry, The University of Tokyo, Hongo, Bunkyoku, Tokyo 113, Japan
| | - Shigeyuki Yokoyama
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 226, Japan, and Department of Biophysics and Biochemistry, The University of Tokyo, Hongo, Bunkyoku, Tokyo 113, Japan
| | - Mitsuo Sekine
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 226, Japan, and Department of Biophysics and Biochemistry, The University of Tokyo, Hongo, Bunkyoku, Tokyo 113, Japan
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20
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Dentino A, Raj P, Bhandary K, Wilson M, Levine M. Role of peptide backbone conformation on biological activity of chemotactic peptides. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55084-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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21
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Raj PA, Soni SD, Ramasubbu N, Bhandary KK, Levine MJ. Crystal structure and solution conformation of S,S'-bis(Boc-Cys-Ala-OMe): intramolecular antiparallel beta-sheet conformation of an acyclic cystine peptide. Biopolymers 1990; 30:73-85. [PMID: 2224052 DOI: 10.1002/bip.360300109] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The conformation of the acyclic biscystine peptide S,S'-bis(Boc-Cys-Ala-OMe) has been studied in the solid state by x-ray diffraction, and in solution by 1H- and 13C-nmr, ir, and CD methods. The peptide molecule has a twofold rotation symmetry and adopts an intramolecular antiparallel beta-sheet structure in the solid state. The two antiparallel extended strands are stabilized by two hydrogen bonds between the Boc CO and Ala NH groups [N...O 2.964 (3) A, O...HN 2.11 (3) A, and NH...O angle 162 (3) degrees]. The disulfide bridge has a right-handed conformation with the torsion angle C beta SSC beta = 95.8 (2) degrees. In solution the presence of a twofold rotation symmetry in the molecule is evident from the 1H- and 13C-nmr spectra. 1H-nmr studies, using solvent and temperature dependencies of NH chemical shifts, paramagnetic radical induced line broadening, and rate of deuterium-hydrogen exchange effects on NH resonances, suggest that Ala NH is solvent shielded and intramolecularly hydrogen bonded in CDCl3 and in (CD3)2SO. Nuclear Overhauser effects observed between Cys C alpha H and Ala NH protons and ir studies provide evidence of the occurrence of antiparallel beta-sheet structure in these solvents. The CD spectra of the peptide in organic solvents are characteristic of those observed for cystine peptides that have been shown to adopt antiparallel beta-sheet structures.
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Affiliation(s)
- P A Raj
- Department of Oral Biology, School of Dental Medicine, State University of New York, Buffalo 14214
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22
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Heitz F, Kaddari F, Van Mau N, Verducci J, Raniri Seheno H, Lazaro R. Ionic pores formed by cyclic peptides. Biochimie 1989; 71:71-6. [PMID: 2470418 DOI: 10.1016/0300-9084(89)90134-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is shown that 2 cyclic tetrapeptides, namely tentoxin and HC toxin, are able to induce the formation of transmembrane ionic channels, although a carrier mechanism could be expected on the basis of their chemical structure (presence of proline or N-methylated residues). Since other cyclic peptides but of larger size, i.e., tyrocidines, gramicidin S (decapeptides) and an octapeptide with a sequence similar to that of HC toxin, are also able to form pores, it appears that this property can be extended to a large number of cyclic peptides. A pore structure based on aggregates is proposed.
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Affiliation(s)
- F Heitz
- Laboratoire de Physico-Chimie des Systèmes Polyphasés, UA-330 du CNRS, Montpellier, France
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23
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Tonge AP, Murray-rust P, Gibbons WA, McLachlan LK. Determination of the major solution conformation of tyrocidine A, using molecular mechanics energy minimization and NMR-derived distance and torsion angle constraints. J Comput Chem 1988. [DOI: 10.1002/jcc.540090511] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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24
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Pastore A, Temussi PA, Salvadori S, Tomatis R, Mascagni P. A conformational study of the opioid peptide dermorphin by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy. Biophys J 1985; 48:195-200. [PMID: 4052557 PMCID: PMC1329310 DOI: 10.1016/s0006-3495(85)83772-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Dermorphin, a natural peptide opioid containing a D-Ala2 residue, has been studied in dimethyl sulfoxide (DMSO) solution by means of several one-dimensional and two-dimensional 1H nuclear magnetic resonance (NMR) methods at various fields from 80 to 600 MHz. The combined use of conventional NMR parameters and of nuclear Overhauser effect effects points to an essentially extended structure. This conformation may be, in part, the result of strong interaction of the amide groups with DMSO molecules.
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25
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Wüthrich K, Billeter M, Braun W. Polypeptide secondary structure determination by nuclear magnetic resonance observation of short proton-proton distances. J Mol Biol 1984; 180:715-40. [PMID: 6084719 DOI: 10.1016/0022-2836(84)90034-2] [Citation(s) in RCA: 624] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The use of proton-proton nuclear Overhauser enhancement (NOE) distance information for identification of polypeptide secondary structures in non-crystalline proteins was investigated by stereochemical studies of standard secondary structures and by statistical analyses of the secondary structures in the crystal conformations of a group of globular proteins. Both regular helix and beta-sheet secondary structures were found to contain a dense network of short 1H-1H distances. The results obtained imply that the combined information on all these distances obtained from visual inspection of the two-dimensional NOE (NOESY) spectra is sufficient for determination of the helical and beta-sheet secondary structures in small globular proteins. Furthermore, cis peptide bonds can be identified from unique, short sequential proton-proton distances. Limitations of this empirical approach are that the exact start or end of a helix may be difficult to define when the adjoining residues form a tight turn, and that unambiguous identification of tight turns can usually be obtained only in the hairpins of antiparallel beta-structures. The short distances between protons in pentapeptide segments of the different secondary structures have been tabulated to provide a generally applicable guide for the analysis of NOESY spectra of proteins.
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26
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Niccolai N, Pogliani L, Rossi C, Corti P, Gibbons WA. Proton relaxation mechanisms and the measurements of r phi, r psi and transannular interproton distances in gramicidin S. Biophys Chem 1984; 20:217-23. [PMID: 6208945 DOI: 10.1016/0301-4622(84)87026-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Monoselective, Rio(SE), biselective, Rio(i,j), and nonselective proton spin-lattice relaxation rates have been measured for dilute solutions of gramicidin S in dimethyl sulfoxide and used to evaluate cross-relaxation rates (sigma ij = Rio(i,j)-Rio(SE)) and Fi ratios (Fi = Ri(NS)/Rio(SE)). The cross-relaxation parameters, sigma, and Fi ratios measured for backbone gramicidin S protons predict that the same correlation time, tau c = 1.2 X 10(-9)s, modulates all the dipolar proton-proton interactions and that these interactions represent the main source for the proton spin-lattice relaxation process. The larger relaxation rates for amide versus alpha-protons of the backbone are attributed to dipolar relaxation between 14N and its directly bonded protons and is an approximate measure of the extent of this. The intrabackbone proton-proton distances, evaluated from sigma values, were consistent with the antiparallel beta-plated sheet/beta II'-turn conformation previously proposed for gramicidin S in solution.
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27
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28
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Williamson MP, Marion D, Wüthrich K. Secondary structure in the solution conformation of the proteinase inhibitor IIA from bull seminal plasma by nuclear magnetic resonance. J Mol Biol 1984; 173:341-59. [PMID: 6699915 DOI: 10.1016/0022-2836(84)90125-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Nuclear magnetic resonance data on the protease inhibitor IIA from bull seminal plasma were used to determine the secondary structure elements in the solution conformation of the protein. The experimental data were obtained from analyses of two-dimensional 1H nuclear magnetic resonance spectra at 500 and 360 MHz and include details of inter-residue nuclear Overhauser enhancements, vicinal spin-spin coupling constants and the sequence location of slowly exchanging amide protons. Accurate measurement of coupling constants and reliable assignments of nuclear Overhauser enhancements were facilitated by the use of absorption mode two-dimensional spectroscopy and large data matrices. It is shown that the peptide backbone is extended from residues 4 to 7, followed by a poorly defined helical region from residues 8 to 13 with a marked change of direction at residue Phe10. Residues 15 to 19 are extended and there is a kink at residue Glu20. Residues 22 to 27 form the central strand of a triple-stranded antiparallel beta-sheet, of which the other two strands are residues 29 to 33 and 49 to 53. Residues 34 to 46 form a helix. The tight turn in the beta-sheet is of type I geometry, and there is a beta-bulge at residue His53.
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29
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Kessler H, Kogler H. Peptidkonformationen, 26 Ein- und zweidimensionale H-NMR-Untersuchungen zur Konformation der beiden cyclischen Pentapeptidecyclo-[Pro-Phe-Gly-Ser-Gly] undcyclo-[Pro-Ser-Gly-Phe-Gly]. ACTA ACUST UNITED AC 1983. [DOI: 10.1002/jlac.198319830216] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Clore GM, Gronenborn AM. Determination of the conformations of cyclic nucleotides bound to the N-terminal core of the cyclic AMP receptor protein of Escherichia coli by 1H-NMR. FEBS Lett 1982; 145:197-202. [PMID: 6290269 DOI: 10.1016/0014-5793(82)80167-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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31
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Gronenborn AM, Clore GM. Conformation of NAD+ bound to yeast and horse liver alcohol dehydrogenase in solution. The use of the proton-proton transferred nuclear Overhauser enhancement. J Mol Biol 1982; 157:155-60. [PMID: 6213784 DOI: 10.1016/0022-2836(82)90518-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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32
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Mendz GL, Moore WJ, Carnegie PR. Proton N.M.R. evidence for secondary and tertiary structure in myelin basic proteins. Biochem Biophys Res Commun 1982; 105:1333-40. [PMID: 6179511 DOI: 10.1016/0006-291x(82)90933-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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33
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Ptak M, Heitz A, Guinand M, Michel G. 400 MHz 1H n.m.r. study of the conformation and self-association of peptidolipin NA. Int J Biol Macromol 1982. [DOI: 10.1016/0141-8130(82)90030-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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