4668-39-7Relevant academic research and scientific papers
Chemical Synthesis of Staphyloferrin B Affords Insight into the Molecular Structure, Iron Chelation, and Biological Activity of a Polycarboxylate Siderophore Deployed by the Human Pathogen Staphylococcus aureus
Madsen, Julie L. H.,Johnstone, Timothy C.,Nolan, Elizabeth M.
, p. 9117 - 9127 (2015)
Staphyloferrin B (SB) is a citrate-based polycarboxylate siderophore produced and utilized by the human pathogen Staphylococcus aureus for acquiring iron when colonizing the vertebrate host. The first chemical synthesis of SB is reported, which enables further molecular and biological characterization and provides access to structural analogues of the siderophore. Under conditions of iron limitation, addition of synthetic SB to bacterial growth medium recovered the growth of the antibiotic resistant community isolate S. aureus USA300 JE2. Two structural analogues of SB, epiSB and SBimide, were also synthesized and employed to investigate how epimerization of the citric acid moiety or imide formation influence its function as a siderophore. Epimerization of the citric acid stereocenter perturbed the iron-binding properties and siderophore function of SB as evidenced by experimental and computational modeling studies. Although epiSB provided growth recovery to S. aureus USA300 JE2 cultured in iron-deficient medium, the effect was attenuated relative to that of SB. Moreover, SB more effectively sequestered the Fe(III) bound to human holo-transferrin, an iron source of S. aureus, than epiSB. SBimide is an imide analogous to the imide forms of other citric acid siderophores that are often observed when these molecules are isolated from natural sources. Here, SBimide is shown to be unstable, converting to native SB at physiological pH. SB is considered to be a virulence factor of S. aureus, a pathogen that poses a particular threat to public health because of the number of drug-resistant strains emerging in hospital and community settings. Iron acquisition by S. aureus is important for its ability to colonize the human host and cause disease, and new chemical insights into the structure and function of SB will inform the search for new therapeutic strategies for combating S. aureus infections. (Chemical Equation Presented).
Koshikamide B, a cytotoxic peptide lactone from a marine sponge Theonella sp
Araki, Takahiro,Matsunaga, Shigeki,Nakao, Yoichi,Furihata, Kazuo,West, Lyndon,Faulkner, D. John,Fusetani, Nobuhiro
, p. 7889 - 7894 (2008/12/23)
(Chemical Equation Presented) Koshikamide B (1) has been isolated from two separate collections of the marine sponge Theonella sp. as the major cytotoxic constituent. Koshikamide B is a 17-residue peptide lactone composed of six proteinogenic amino acids, two D-isomers of proteinogenic amino acids, seven N-methylated amino acids, and two unusual amino acid residues. The unusual amino acids are Nδ-carbamoylasparagine and 2-(3-amino-2-hydroxy-5- oxopyrrolidin-2-yl)propionic acid (AHPP); the former is first found as the constituent of peptides, whereas the latter is a new amino acid residue. The N-terminus of koshikamide B is blocked by a methoxyacetyl group. The structure of koshikamide B (1) has been determined by interpretation of spectral data and analysis of chemical degradation products. Koshikamide B (1) exhibits cytotoxicity against P388 murine leukemia cells and the human colon tumor (HCT-116) cell line with an IC50 value of 0.45 and 7.5 μg/mL, respectively.
AMINO ACID SURROGATES : AN INDIRECT METHOD FOR THE SYNTHESIS OF PEPTIDES CONTAINING THE THIOASPARAGINYL RESIDUE
Saneii, Hossain,Spatola, Arno F.
, p. 149 - 152 (2007/10/02)
The protected pentapeptide, Boc-Tan-Cys(PMB)-Pro-Leu-GlyNH2 and related thioasparaginyl compounds were prepared by an indirect method from their corresponding β-cyanoalanyl precursors by treatment with H2S/NH3.The optical purities of thioasparagine (Tan)
