scholarly journals Structural elucidation of XR586, a peptaibol-like antibiotic from Acremonium persicinum

1996 ◽  
Vol 320 (3) ◽  
pp. 723-728 ◽  
Author(s):  
Gary J. SHARMAN ◽  
Andrew C. TRY ◽  
Dudley H. WILLIAMS ◽  
A. Martyn AINSWORTH ◽  
Richard BENEYTO ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Fast Atom Bombardment ◽  
Culture Collection ◽  
Helical Conformation ◽  
British Library ◽  
Chemical Shift Assignments ◽  
Enzymic Digestion ◽  
C Terminus ◽  
Collection Number ◽  
Fast Atom Bombardment Ms

A novel peptide, XR586, has been isolated from fermentations of Acremonium persicinum (Xenova culture collection number X21488). The structure of XR586 has been elucidated by means of NMR spectroscopy, electrospray and fast-atom bombardment MS, derivatization and enzymic digestion. It has been shown to be helical by CD measurements. XR586 shows many structural and conformational features in common with peptaibols, particularly the zervamicins. Peptaibol antibiotics are peptides, typically of 15–20 residues, containing a large proportion of α-aminoisobutyric acid (Aib) residues. These peptides adopt a helical conformation in solution and display anti-bacterial and toxic properties due to their ability to form pores in membranes. However, while XR586 contains several Aib residues, it lacks a terminal phenylalaninol and terminates in the sequence Phe-Gly. The lack of reduction of the penultimate residue at the C-terminus may indicate that this step is normally at the end of the biosynthetic pathway of peptaibols and occurs with cleavage of Gly. The 1H chemical shift assignments of XR586 are reported in Supplementary Publication SUP 50179 (3 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1996) 313, 9 (‘Deposition of data’).

scholarly journals Photoaffinity labelling of cyanomethaemoglobin with derivatives of tryptophan and 5-bromotryptophan

1995 ◽  
Vol 308 (1) ◽  
pp. 251-260 ◽  
Author(s):  
M Li ◽  
Z Lin ◽  
M E Johnson
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Tryptic Peptide ◽  
Fast Atom Bombardment ◽  
Binding Mode ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Photoaffinity Labelling ◽  
Derivatives Of ◽  
Fast Atom Bombardment Ms

Tryptophan and 5-bromotryptophan (5-BrTrp) are relatively potent inhibitors of sickle-haemoglobin polymerization. The binding sites of these compounds to normal and sickle haemoglobin (HBA and HBS) have been suggested, but not firmly established, through the use of spin-labelled derivatives and/or computer modeling. In the present study we approached the problem by utilizing the technique of photoaffinity labelling. The cyanomet forms of HBA and HBS were subjected to photoaffinity labelling with N alpha-(4-azidotetrafluorobenzoyl)tryptophan and N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan respectively. Both irradiated samples of HBA and HBS were denatured, digested with trypsin, and then separated by reversed-phase HPLC. A labelled tryptic peptide was isolated from the photolabelling of HBS with N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan. The peptide was identified to be Val1(alpha)-Lys7(alpha), with the label attached to Val1(alpha), by virtue of amino acid analysis and sequencing, in conjunction with fast-atom-bombardment MS. The binding mode of N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan is proposed and its relevance to the potency of the 5-BrTrp-based anti-sickling agents is discussed.

scholarly journals Figainin 1, a Novel Amphibian Skin Peptide with Antimicrobial and Antiproliferative Properties

Antibiotics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 625 ◽  
Author(s):  
Carlos José Correia Santana ◽  
Ana Carolina Martins Magalhães ◽  
Agenor C. M. dos Santos Júnior ◽  
Carlos André Ornelas Ricart ◽  
Beatriz D. Lima ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Helical Conformation ◽  
Amino Acid Residues ◽  
Amphibian Skin ◽  
Gram Positive Bacteria ◽  
C Terminus ◽  
Ic50 Values ◽  
Amphibian Skin Peptide ◽  
Hydrophobic Amino Acids ◽  
Skin Secretions

Amphibian skin secretions are abundant in bioactive compounds, especially antimicrobial peptides. These molecules are generally cationic and rich in hydrophobic amino acids, have an amphipathic structure and adopt an α-helical conformation when in contact with microorganisms membranes. In this work, we purified and characterized Figainin 1, a novel antimicrobial and antiproliferative peptide from the cutaneous secretion of the frog Boana raniceps. Figainin 1 is a cationic peptide with eighteen amino acid residues—rich in leucine and isoleucine, with an amidated C-terminus—and adopts an α-helical conformation in the presence of trifluoroethanol (TFE). It displayed activity against Gram-negative and especially Gram-positive bacteria, with MIC values ranging from 2 to 16 µM, and showed an IC50 value of 15.9 µM against epimastigote forms of T. cruzi; however, Figanin 1 did not show activity against Candida species. This peptide also showed cytolytic effects against human erythrocytes with an HC50 of 10 µM, in addition to antiproliferative activity against cancer cells and murine fibroblasts, with IC50 values ranging from 10.5 to 13.7 µM. Despite its adverse effects on noncancerous cells, Figainin 1 exhibits interesting properties for the development of new anticancer agents and anti-infective drugs against pathogenic microorganisms.

Characterization of a putative α-mannosyltransferase involved in phosphatidylinositol trimannoside biosynthesis in Mycobacterium tuberculosis

2002 ◽  
Vol 363 (3) ◽  
pp. 437-447 ◽  
Author(s):  
Laurent KREMER ◽  
Sudagar S. GURCHA ◽  
Pablo BIFANI ◽  
Paul G. HITCHEN ◽  
Alain BAULARD ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fast Atom Bombardment ◽  
Sequence Similarity ◽  
Alternate Pathway ◽  
Redundant Gene ◽  
A Cell ◽  
Molecular Aspects ◽  
Biosynthetic Machinery ◽  
Fast Atom Bombardment Ms

Phosphatidyl-myo-inositol mannosides (PIMs), lipomannan (LM) and lipoarabinomannan (LAM) are an important class of bacterial factors termed modulins that are found in tuberculosis and leprosy. Although their structures are well established, little is known with respect to the molecular aspects of the biosynthetic machinery involved in the synthesis of these glycolipids. On the basis of sequence similarity to other glycosyltransferases and our previous studies defining an α-mannosyltransferase from Mycobacterium tuberculosis, named PimB [Schaeffer, Khoo, Besra, Chatterjee, Brennan, Belisle and Inamine (1999) J. Biol. Chem. 274, 31625–31631], which catalysed the formation of triacyl (Ac3)-PIM2 (i.e. the dimannoside), we have identified a related gene from M. tuberculosis CDC1551, now designated pimC. The use of a cell-free assay containing GDP-[14C]mannose, amphomycin and membranes from Myobacterium smegmatis overexpressing PimC led to the synthesis of a new alkali-labile PIM product. Fast-atom-bombardment MS established the identity of the new enzymically synthesized product as Ac3PIM3 (i.e. the trimannoside). The results indicate that pimC encodes an α-mannosyltransferase involved in Ac3PIM3 biosynthesis. However, inactivation of pimC in Myobacterium bovis Bacille Calmette—Guérin (BCG) did not affect the production of higher PIMs, LM and LAM when compared with wild-type M. bovis BCG, suggesting the existence of redundant gene(s) or an alternate pathway that may compensate for this PimC deficiency. Further analyses, which compared the distribution of pimC in a panel of M. tuberculosis strains, revealed that pimC was present in only 22% of the clinical isolates examined.

scholarly journals Type IX Secretion System Cargo Proteins Are Glycosylated at the C Terminus with a Novel Linking Sugar of the Wbp/Vim Pathway

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Paul D. Veith ◽  
Mikio Shoji ◽  
Richard A. J. O’Hair ◽  
Michael G. Leeming ◽  
Shuai Nie ◽  
...  
Keyword(s):  
Cell Surface ◽  
Porphyromonas Gingivalis ◽  
Biosynthetic Pathway ◽  
Secretion System ◽  
Tannerella Forsythia ◽  
Diverse Range ◽  
Content Type ◽  
C Terminus ◽  
Cargo Proteins ◽  
Type Ix Secretion System

ABSTRACT Porphyromonas gingivalis and Tannerella forsythia use the type IX secretion system to secrete cargo proteins to the cell surface where they are anchored via glycolipids. In P. gingivalis, the glycolipid is anionic lipopolysaccharide (A-LPS), of partially known structure. Modified cargo proteins were deglycosylated using trifluoromethanesulfonic acid and digested with trypsin or proteinase K. The residual modifications were then extensively analyzed by tandem mass spectrometry. The C terminus of each cargo protein was amide-bonded to a linking sugar whose structure was deduced to be 2-N-seryl, 3-N-acetylglucuronamide in P. gingivalis and 2-N-glycyl, 3-N-acetylmannuronic acid in T. forsythia. The structures indicated the involvement of the Wbp pathway to produce 2,3-di-N-acetylglucuronic acid and a WbpS amidotransferase to produce the uronamide form of this sugar in P. gingivalis. The wbpS gene was identified as PGN_1234 as its deletion resulted in the inability to produce the uronamide. In addition, the P. gingivalis vimA mutant which lacks A-LPS was successfully complemented by the T. forsythia vimA gene; however, the linking sugar was altered to include glycine rather than serine. After removal of the acetyl group at C-2 by the putative deacetylase, VimE, VimA presumably transfers the amino acid to complete the biosynthesis. The data explain all the enzyme activities required for the biosynthesis of the linking sugar accounting for six A-LPS-specific genes. The linking sugar is therefore the key compound that enables the attachment of cargo proteins in P. gingivalis and T. forsythia. We propose to designate this novel linking sugar biosynthetic pathway the Wbp/Vim pathway. IMPORTANCE Porphyromonas gingivalis and Tannerella forsythia, two pathogens associated with severe gum disease, use the type IX secretion system (T9SS) to secrete and attach toxic arrays of virulence factor proteins to their cell surfaces. The proteins are tethered to the outer membrane via glycolipid anchors that have remained unidentified for more than 2 decades. In this study, the first sugar molecules (linking sugars) in these anchors are identified and found to be novel compounds. The novel biosynthetic pathway of these linking sugars is also elucidated. A diverse range of bacteria that do not have the T9SS were found to have the genes for this pathway, suggesting that they may synthesize similar linking sugars for utilization in different systems. Since the cell surface attachment of virulence factors is essential for virulence, these findings reveal new targets for the development of novel therapies.

scholarly journals Structural determination of a 5-O-methyl-deaminated neuraminic acid (Kdn)-containing polysaccharide isolated from Sinorhizobium fredii

1998 ◽  
Vol 334 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Antonio M. GIL-SERRANO ◽  
Miguel A. ÍGUEZ-CARVAJAL RODR ◽  
Pilar TEJERO-MATEO ◽  
José L. ESPARTERO ◽  
Jane THOMAS-OATES ◽  
...  
Keyword(s):  
Fast Atom Bombardment ◽  
Wild Type Strain ◽  
Auxotrophic Mutant ◽  
Neuraminic Acid ◽  
Wild Type ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
In The Wild ◽  
Fast Atom Bombardment Ms

The structure of a polysaccharide from Sinorhizobium frediiSVQ293, a thiamine auxotrophic mutant of S. fredii HH103, has been determined. This polysaccharide was isolated following the protocol for lipopolysaccharide extraction. On the basis of monosaccharide analysis, methylation analysis, fast atom bombardment MS, collision-induced dissociation tandem MS, one-dimensional 1H and 13C NMR and two-dimensional NMR experiments, the structure was shown to consist of the following trisaccharide repeating unit → 2)-α-d-Galp-(1 → 2)-β-d-Ribf-(1 → 9)-α-5-O-Me-Kdnp-(2 →, in which Kdn stands for deaminated neuraminic acid; 25% of the Kdn residues are not methylated. The structure of this polysaccharide is novel and this is the first report of the presence of Kdn in a rhizobial polysaccharide, as well as being the first structure described containing 5-O-Me-Kdn. This Kdn-containing polysaccharide is not present in the wild-type strain HH103, which produces a 3-deoxy-d-manno-2-octulosonic acid (Kdo)-rich polysaccharide. We conclude that it is likely that the appearance of this new Kdn-containing polysaccharide is a consequence of the mutation.

scholarly journals The amino acid sequence of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015

1973 ◽  
Vol 135 (4) ◽  
pp. 751-758 ◽  
Author(s):  
R. P. Ambler
Keyword(s):  
Amino Acid ◽  
Cytochrome C ◽  
Amino Acid Sequence ◽  
Attachment Site ◽  
Photosynthetic Bacterium ◽  
Chromatium Vinosum ◽  
British Library ◽  
Pseudomonas Denitrificans ◽  
Single Polypeptide Chain ◽  
C Terminus

The amino acid sequence of the cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015 (Iwasaki's ‘Pseudomonas denitrificans’) has been determined. This organism is the only non-photosynthetic bacterium in which the protein has been found. The protein consists of a single polypeptide chain of 127 residues, with a single haem covalently attached to two cysteines. Unlike normal cytochromes c, the haem attachment site is very close to the C-terminus. The amino acid sequence around the haem attachment site is very similar to that of Chromatium vinosum D cytochrome c′. Detailed evidence for the amino acid sequence of the protein has been deposited as Supplementary Publication SUP 50022 at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.

Structure of a three-dimensional domain-swapped dimer of theHelicobacter pyloritype IV secretion system pilus protein CagL

2014 ◽  
Vol 70 (5) ◽  
pp. 1391-1400 ◽  
Author(s):  
Stephan Barden ◽  
Benjamin Schomburg ◽  
Jens Conradi ◽  
Steffen Backert ◽  
Norbert Sewald ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Crystal Form ◽  
Structural Features ◽  
Secretion System ◽  
Helical Conformation ◽  
Domain Swap ◽  
Helix Bundle ◽  
Type Iv ◽  
C Terminus ◽  
Dimensional Domain

A new crystal form of theHelicobacter pyloritype IV secretion system (T4SS) pilus protein CagL is described here. In contrast to two previously reported monomeric structures, CagL forms a three-dimensional domain-swapped dimer. CagL dimers can arise during refolding from inclusion bodies or can form spontaneously from purified monomeric CagL in the crystallization conditions. Monomeric CagL forms a three-helix bundle, with which the N-terminal helix is only loosely associated. In the new crystal form, the N-terminal helix is missing. The domain swap is owing to exchange of the C-terminal helix between the two protomers of a dimer. A loop-to-helix transition results in a long helix of 108 amino acids comprising the penultimate and the last helix of the monomer. The RGD motif of dimeric CagL adopts an α-helical conformation. In contrast to the previously reported structures, the conserved and functionally important C-terminal hexapeptide is resolved. It extends beyond the three-helix bundle as an exposed helical appendage. This new crystal form contributes to the molecular understanding of CagL by highlighting rigid and flexible regions in the protein and by providing the first view of the C-terminus. Based on the structural features, a previously unrecognized homology between CagL and CagI is discussed.

Labeled Fumonisins: Production and Use of Fumonisin B1 Containing Stable Isotopes

1994 ◽  
Vol 77 (2) ◽  
pp. 525-532 ◽  
Author(s):  
Ronald D Plattner ◽  
Bruce E Branham
Keyword(s):  
Fast Atom Bombardment ◽  
Internal Standard ◽  
Fumonisin B1 ◽  
The Other ◽  
Gas Chromatography Mass Spectrometry ◽  
Methyl Groups ◽  
Liquid Cultures ◽  
Corn Products ◽  
Precision And Accuracy ◽  
Fast Atom Bombardment Ms

Abstract Fumonisin B1 (FB1) labeled on the branch methyl groups with deuterium was produced in liquid cultures, and methyl-D3-labeled methionine was added. The isolated FB1 had 90% incorporation of 6 deuterium atoms and 9% incorporation of 3 deuterium atoms. The labeled FB1 was used as an internal standard for 2 analytical methods to measure FB1 in extracts of corn, corn products, and cultures. One method was hydrolysis followed by gas chromatography/mass spectrometry (GC/MS) of the derivatized backbone, and the other was analysis by fast atom bombardment MS (FAB/MS). Incorporation of labeled FB1 into samples resulted in a GC/MS method with improved precision and accuracy and allowed for a quantitative FAB/MS method.

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