Circulins A and B. Novel human immunodeficiency virus (HIV)-inhibitory macrocyclic peptides from the tropical tree Chassalia parvifolia.

Gustafson, Kirk R.; Sowder, Raymond C.; Henderson, Louis E.; Parsons, Ian; Kashman, Yoel; Cardellina, John H.; McMahon, James B.; Buckheit, Robert W.; Pannell, Lewis K.; Boyd, Michael R.

doi:10.1021/ja00099a064

Cited by 287 publications

(262 citation statements)

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“…For example, both cTP-14a and its retroisomer rcTP-14b are broadly active. Under low salt conditions, cTP-14a missing the four hydrophobic residues in the D ring of cTP-18 (Cys 7,12 , Tyr 8 , and Ile 11 ) but retaining six cationic amino acids shows comparable antimicrobial activity (within 2-fold difference) of cTP-18 in eight of ten test organisms with E. coli and E. faecalis being exceptions. Under high salt conditions and again comparing to cTP-18, cTP-14a shows a selective decrease of 3-9-fold in potency against three of the four test Gram-negative bacteria but only one of the three Gram-positive bacteria (Table III).…”

Section: Table IV Antimicrobial Activity Of Cctp-14 and Their Analoguesmentioning

confidence: 99%

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Correlations of Cationic Charges with Salt Sensitivity and Microbial Specificity of Cystine-stabilized β-Strand Antimicrobial Peptides

Tam

Yang

2002

Journal of Biological Chemistry

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The electrostatic interaction of the charge cluster of an amphipathic peptide antibiotic with microbial membranes is a salt-sensitive step that often determines organism specificity. We have examined the correlation between charge clusters and salt insensitivity and microbial specificity in linear, cyclic, and retro-isomeric cystine-stabilized ␤-strand (CS␤) tachyplesin (TP) in a panel of 10 test organisms. Cyclic tachyplesins consisting of 14 and 18 amino acids are constrained by an end-to-end peptide backbone and two or three disulfide bonds to cross-brace the anti-parallel ␤-strand that approximates a "␤-tile" structure. Circular dichroism measurements of ␤-tile TPs showed that they displayed ordered structures. Control peptides containing the same number of basic amino acids as TP but lacking disulfide constraints were highly salt sensitive. Cyclic TP analogues with six cationic charges were more broadly active and salt-insensitive than those with fewer cationic charges. Reducing their proximity or number of cationic charges, particularly those with three or fewer basic amino acids, led to a significant decrease in potency and salt insensitivity, but an increased selectivity to certain Gram-positive bacteria. An end-group effect of the dibasic N-terminal Lys of TP in the open-chain TP and its retroisomer was observed in certain Gram-negative bacteria under high-salt conditions, an effect that was not found in the cyclic analogs. These results suggest that a stable folded structure together with three or more basic amino acids closely packed in a charged region in CS␤ peptides is important for salt insensitivity and organism specificity.

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Section: Table IV Antimicrobial Activity Of Cctp-14 and Their Analoguesmentioning

confidence: 99%

“…Cyclic CS␤ antimicrobial peptides known as cyclotides have also been discovered in plants and animals (12)(13)(14)(15)(16). These end-to-end constrained peptides include the Rhesus theta defensin (RTD-1) that has been identified from Rhesus monkey leukocytes (17).…”

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confidence: 99%

Correlations of Cationic Charges with Salt Sensitivity and Microbial Specificity of Cystine-stabilized β-Strand Antimicrobial Peptides

Tam

Yang

2002

Journal of Biological Chemistry

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“…They are found in a variety of dicot plants, including the Cucurbitaceae (10), Rubiaceae (11), Violaceae (12,13), Fabaceae (9,14), and Solanaceae families (15). They are ribosomally synthesized as linear precursors, excised at the N and C termini of their mature cyclotide domains, and then head-to-tail ligated to produce mature cyclic peptides (4).…”

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confidence: 99%

Discovery of Linear Cyclotides in Monocot Plant Panicum laxum of Poaceae Family Provides New Insights into Evolution and Distribution of Cyclotides in Plants

Nguyen

Lian

Pang

et al. 2013

Journal of Biological Chemistry

113

112

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Background: Cyclotides are biologically active, plant-derived macrocyclic peptides. All cyclotides and their acyclic variants have been isolated from dicots. Results: We characterized nine novel linear cyclotides from monocot plant Panicum laxum. Conclusion: Our study provides the first evidence of linear cyclotides at the protein level in the Poaceae. Significance: Ancient linear cyclotide analogs may have existed before the divergence of dicots and monocots.

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“…[4] It is believed that the compact CCK motif of cyclotides is responsible for their exceptional resistance against chemical, thermal, and proteolytic degradation. [5] Cyclotides display a diverse range of biological activities, including uterotonic, [6] haemolytic, [7][8][9] neurotensin antagonistic, [10] HIV inhibitory, [11] antimicrobial, [12] cytotoxic, [13] antifouling, [14] and trypsin inhibitory activities. [15] In addition, kalata B1 and B2 have been shown to inhibit the growth and development of Helicoverpa punctigera and H. armigera larvae, suggesting that cyclotides function as insecticidal agents as part of plant defence systems.…”

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confidence: 99%

Structure and Activity of the Leaf-Specific Cyclotide vhl-2

et al. 2010

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Cyclotides are plant-derived macrocyclic peptides with potential applications in the pharmaceutical and agricultural industries. In addition to their presumed natural function as host-defence peptides arising from their insecticidal activity, their other biological activities include antimicrobial, haemolytic, and cytotoxic activities, but at present, only limited information is available on the structural and chemical features that are important for these various activities. In the current study, we determined the three-dimensional structure of vhl-2, a leaf-specific cyclotide. Although the characteristic cyclic cystine knot fold of other cyclotides is maintained in vhl-2, it has more potent haemolytic activity than well-characterized cyclotides such as kalata B1 and kalata B8. Analysis of surface hydrophobicity and haemolytic activity for a range of cyclotides indicates a correlation between them, with increasing hydrophobicity resulting in increased haemolytic activity. This correlation is consistent with membrane binding being a vital step in mediating the various cytotoxic activities of cyclotides. The gene sequence for vhl-2 was determined and indicates that vhl-2 is processed from a multidomain precursor protein that also encodes the cyclotide cycloviolacin H3.

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Circulins A and B. Novel human immunodeficiency virus (HIV)-inhibitory macrocyclic peptides from the tropical tree Chassalia parvifolia.

Cited by 287 publications

References 0 publications

Correlations of Cationic Charges with Salt Sensitivity and Microbial Specificity of Cystine-stabilized β-Strand Antimicrobial Peptides

Correlations of Cationic Charges with Salt Sensitivity and Microbial Specificity of Cystine-stabilized β-Strand Antimicrobial Peptides

Discovery of Linear Cyclotides in Monocot Plant Panicum laxum of Poaceae Family Provides New Insights into Evolution and Distribution of Cyclotides in Plants

Structure and Activity of the Leaf-Specific Cyclotide vhl-2

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