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B Bodo

Publications and source records attributed to B Bodo.

49 records · Page 3Linked to original sources
PubMed1995

Trichorzins HA and MA, antibiotic peptides from Trichoderma harzianum. II. Sequence determination.

A series of 18-residue antibiotic-antifungal peptides, trichorzins HA and MA, were isolated from Trichoderma harzianum strains exhibiting antagonistic properties against phytopathogenic fungi. The sequences of the nine major pure peptides isolated by HPLC were determined by positive ion FAB-MS data and two-dimensional NMR measurements, including COSY, HOHAHA, ROESY and 1H-13C LRCOSY experiments.

Amino Acid Sequence↗
PubMed1994

Cinnamrutinoses A and B, glycosides of Populus tremula.

The cinnamylrutinosides, cinnamrutinoses A and B, were isolated along with known phenolic glucosides, from the stem bark of Populus tremula infected with the pathogenic fungus Hypoxylon mammatum. The structures were determined from spectroscopic and chemical evidence.

Carbohydrate Sequence↗
PubMed1994

Patuletin acetylrhamnosides from Kalanchoe brasiliensis as inhibitors of human lymphocyte proliferative activity.

The fractionation of the juice of fresh stems and leaves of Kalanchoe brasiliensis was monitored by an assay measuring lymphocyte proliferative activity and allowed the isolation and identification of seven patuletin rhamnoside derivatives [1-7]. Three of them are novel, namely, patuletin 3-O-(4"-O-acetyl-alpha-L-rhamnopyranosyl)-7-O-(2'"-O-acetyl- alpha-L-rhamnopyranoside) [1], patuletin 3-O-alpha-L-rhamnopyranosyl-7-O-(2'"-O-acetyl-alpha-L- rhamnopyranoside) [3], and patuletin 3-O-(4"-O-acetyl-alpha-L-rhamnopyranosyl)-7-O- rhamnopyranoside [4], and four are known [2, 5-7]. Their structures were determined by the analysis of 1H-1H and 1H-13C COSY nmr, ci, and fab mass spectra.

Chromones↗
PubMed1993

Sequence and solution conformation of the 20-residue peptaibols, saturnisporins SA II and SA IV.

Saturnisporins SA II and SA IV are the major components of the 20-residue peptaibol mixture isolated from a culture of the fungus Trichoderma saturnisporum. These peptides exhibit antibiotic activity against Staphylococcus aureus. Their sequences were derived from unequivocal methodology implying the combined use of positive ion FAB mass spectrometry and NMR: the majority of the sequences result from mass spectrometry fragmentations and the location of isomeric residues arises either from analysis of ROESY cross-peaks between contiguous amide protons or from heteronuclear 2J or 3J 1H-13C couplings detected in long-range 1H-13C COSY experiments. The sequence specific 1H and 13C NMR assignments are described. Saturnisporins SA II and SA IV exhibit similar secondary structures, as deduced from their ROESY patterns and 3JNHC alpha H coupling constant values, together with amide hydrogen-deuterium exchange rates and temperature coefficients of amide and carbonyl groups. An overall alpha-helical structure is proposed, maintaining two regions of distortion to this regular structure; i) the N-terminal part, which contains 3(10) and mixed alpha-3(10) turns, and ii) the Aib10-Val15 region, including a Pro residue which accommodates a bend stabilized by two 3(10) H-bonds.

Amino Acid Sequence↗
PubMed1992

Membrane-modifying properties of the pore-forming peptaibols saturnisporin SA IV and harzianin HA V.

Harzianin HA V and saturnisporin SA IV are alpha-amino isobutyric-containing peptides with 18- and 20-residue chain length, respectively. They were isolated from in vitro cultures of Trichoderma species and their sequences were determined by the combined use of positive ion FAB mass spectrometry and NMR. In organic solvent solution, both peptides exhibited the same predominant alpha-helical secondary structure including a hinge at the level of the central Pro residue, as deduced from NMR data. Their interaction with neutral phospholipid bilayers was shown to induce leakage of the material entrapped in small unilamellar vesicles composed of egg phosphatidylcholine/cholesterol (7/3). When incorporated into neutral planar lipid bilayers, they promoted voltage-gated channels. The concentration- and voltage-dependences of the ionic conductances induced by these peptides were studied in macroscopic current-voltage experiments. Single-channel measurements showed that whilst SA IV developed non-integral multi-open states similar to those induced by alamethicins, but with faster kinetics, the shorter analogue, HA V promoted much smaller-sized conducting aggregates in agreement with macroscopic conductance data.

Amino Acid Sequence↗
PubMed1991

Tricholongins BI and BII, 19-residue peptaibols from Trichoderma longibrachiatum. Solution structure from two-dimensional NMR spectroscopy.

Two nonadecapeptides, tricholongins BI and BII, which display antifungal and antibacterial activities, have been isolated from in vitro cultures of the fungus Trichoderma longibrachiatum. The peptides were separated by reversed-phase HPLC; their amino acid compositions were determined by gas chromatography and their sequences by positive-ion fast-atom-bombardment mass spectrometry and high-field NMR. These linear peptides, containing mainly hydrophobic L-amino acids, 8-9 2-aminoisobutyric acid residues and exhibiting an acetylated N-terminal residue and an amino alcohol C-terminal leucinol belong to the peptaibol class. The methanol solution structure of tricholongins BI and BII has been investigated using both one- and two-dimensional NMR techniques. The total 1H-NMR and 13C-NMR assignments are given. By a combination of the 3JNH,C alpha H coupling constant values, temperature coefficients of the NH and CO groups, amide hydrogen/deuterium-exchange rate measurements and NOE data, a secondary structure for tricholongins in solution has been proposed. Both peptides adopt a similar alpha-helical conformation with a hinge around Pro13 resulting from two 3(10) bonds. The results suggest that the N-terminus contains mixed alpha/3(10) bonds. The membrane permeability modifications induced by tricholongins have been assayed by the use of liposomes composed of egg phosphatidylcholine with 20-30% cholesterol. The peptide-induced leakage of an entrapped fluorescent probe has been followed by fluorescence spectroscopy. In a concentration range of 0.13-0.31 microM, tricholongins induce the leakage of 50% of the entrapped material in 20 min.

Amino Acid Sequence↗
PubMed1989

Interaction of trichorzianines A and B with model membranes and with the amoeba Dictyostelium.

Trichorzianines A (TA) and B (TB) are microheterogeneous mixtures of antibiotic nonadecapeptides of the peptaibol class which interact with lipidic membranes and modify their permeability properties. The TB differ from the TA by replacement of the Gln-18 by a Glu, giving rise to a C-terminal negative charge at neutral pH. The role of this charge on the trichorzianine-lipid interaction was investigated with model membranes by fluorescence spectroscopy and the results were correlated with the biological activity toward the amoeba Dictyostelium discoideum. The interaction of the acidic trichorzianine TB IIIc (Glu-18) with phospholipid bilayers and the subsequent induced permeability were weaker than that exhibited by the uncharged TA IIIc (Gln-18) and MeTB IIIc (TB IIIc monomethyl ester). The unfavourable effect of the negative charge in TB IIIc was strongly enhanced by incorporation of cholesterol in the bilayer. Similarly, TA IIIc as well as MeTB IIIc induced growth inhibition and lysis of the amoeba Dictyostelium at four times lower concentrations than TB IIIc. The results suggested that the interaction of trichorzianines with the phospholipid bilayer and the subsequent modifications of permeability were involved in the inhibitory properties and cell lysis induced by trichorzianines toward Dictyostelium.

Amino Acid Sequence↗
PubMed1989

Isolation, sequence, and conformation of seven trichorzianines B from Trichoderma harzianum.

From the antagonistic fungus Trichoderma harzianum, a group of acidic new peptides, trichorzianines B (TB), was isolated in addition to neutral trichorzianines A (TA) previously studied. TA and TB exhibit various biological activities related to their membrane properties and a different behaviour of the two groups was noticed. As observed for other peptaibols, TB consist in a microheterogeneous mixture which was resolved into pure peptides by reversed-phase C18 HPLC. The sequence of the seven main isolated TB, namely TB IIa, TB IIIc, TB IVb, TB Vb, TB VIa, TB VIb, TB VII, was determined by the combined use of positive ion FAB mass spectrometry and 2D 1H n.m.r. spectroscopy, including COSY and NOESY experiments. TB differ from the corresponding TA only by the replacement of Gln 18 in the TA sequence by a glutamic acid. The 1H n.m.r. data suggested that the TB are mainly organized in an alpha helix.

Amino Acid Sequence↗
PubMed1987

Isolation and sequence determination of trichorzianines A antifungal peptides from Trichoderma harzianum.

Trichorzianines A, membrane active peptides of the peptaibol class, were isolated from cultures of the mould Trichoderma harzianum. Trichorzianines A were separated into pure components by HPLC on octadecyl bonded and SiO2 phases successively. Nine trichorzianines A (IIa, IIIa, IIIb, IIIc, IVb, Vb, VIa, VIb and VII) were isolated from the complex microheterogeneous mixture. Their N-terminal amino acid is acetylated, the C-terminal amino alcohol is either tryptophanol or phenylalaninol, 7 to 8 of the 19 residues are alpha-aminoisobutyric acid. Gas chromatography on a chiral phase showed isovaline to have the D-configuration and all the other optically active amino acids and amino alcohols to have the L-configuration. The amino acid sequences were determined from their positive ion FAB mass spectra which exhibited the preferential cleavage of the Aib 12-Pro 13 amide bond as a main fragmentation. The resulting fragments subsequently underwent amide bond ruptures that generated two series of abundant acylium ions which enabled direct determination of the 1-19 sequence. The relative position of the isomeric amino acids in the sequence of trichorzianine AVII was assigned from analysis of the N- and C-terminal oligopeptides yielded by its selective acidic hydrolysis. The microheterogeneity of trichorzianines A results mainly from single or multiple substitution of amino acids at the specific positions 5, 14, 16 and 19.

Amino Acid Sequence↗
PubMed1986

Fluorescence studies of the interaction of trichorzianine A IIIc with model membranes.

The biological activity and the chemical structure of the lipophilic peptides, trichorzianines, suggested that these substances could act on membrane permeability. The interaction of a major component of trichorzianines, trichorzianine A IIIc (TA IIIc), a 19-residue peptaibol containing tryptophanol as C-terminal amino-alcohol, with some synthetic phospholipid vesicles (egg phosphatidylcholine (egg PC), dipalmitoylphosphatidylcholine (DPPC) and sterol-containing egg PC) was studied by fluorescence spectroscopy. TA IIIc was found to bind to lipid vesicles either in liquid-crystalline or gel state. The accessibility to the aqueous phase of the embedded peptide was examined for various phospholipid compositions by fluorescence quenching experiments. We found that incorporation of TA IIIc in egg PC vesicles leads to reduced accessibility of the C-terminal tryptophanol to external quenchers, whereas when sterols are present in the bilayer, this accessibility is higher, consistent with a higher exposure of the chromophore to the aqueous phase. TA IIIc was shown to induce leakage of vesicular entrapped material. Incorporation of sterols in the bilayer seems to influence the position of the bound peptide within the bilayer but not its action on the membrane permeability.

Amino Acid Sequence↗
PubMed1983

Crystallization and preliminary X-ray diffraction results of trichorzianine A 1, a peptide with nineteen residues from Trichoderma harzianum.

Trichorzianine A 1 is one of the main components of a mixture of related antibiotic peptides (trichorzianines) produced by the fungus Trichoderma harzianum. Good crystals were obtained and allowed X-ray diffraction up to 0.8 A resolution. The space group is orthorhombic, C222(1), Z = 8, a = 64.8 (1) A, b = 9.33 (3) A, c = 39.9 (1) A. The solvent content is only 12%, preventing a heavy ion diffusion. So, we are trying to obtain the structure by direct methods.

Amino Acids↗
PubMed1983

High field NMR study of antibiotic peptides: 1H assignment of trichorzianine A1 spectra by 2D experiments.

A new antibiotic peptide, trichorzianine A1, was isolated from a culture of Trichoderma harzianum. It contains 19 residues, the N terminus is blocked by an acetyl group and the C terminus is tryptophanol. As a first part of the structural study of this new peptide, we here present the analysis of the 1H NMR spectrum accomplished by 2 DJ resolved and spin echo correlated spectroscopy.

Amides↗