Studies on the biosynthesis of paraherquamide. Construction of the amino acid framework
摘要:
It has been previously established in this laboratory that the beta -methyl-beta -hydroxyproline moiety of the potent anthelmintic agent paraherquamide A, is biosynthetically derived from L-isoleucine. The downstream events from L-Ile to paraherquamide A have now been investigated. The synthesis of [1-(13)C]-labeled L-beta -methylproline is described by means of a Hoffman-Loeffler-Freytag reaction sequence from [1-(13)C]-L-Ile. This amino acid is shown to be a direct biosynthetic precursor to paraherquamide A by feeding and incorporation experiments in growing cultures of Penicillum fellutanum. Three tryptophan-containing dipeptides of L-beta -methylproline have been constructed: [(13)C(2)]-2-(l,1-dimethyl-2-propenyl)-L-tryptophanyl-3(S)-methyl-L-proline [(13)C(2)]-3(S)-methyl-L-prolyl-2-(l,1-dimethyl-2-propenyl)-L-tryptophan and [(13)C(2)]-cyclo-2-(l,1-dimethyl-2-propenyl)-L-tryptophan-3(S)-methyl-L-proline. [alpha-(15)N, 1-(13)C]-2-(1,1-Dimethyl-2-propenyl)-L-tryptophan was also prepared but none of these substances were found to serve as biosynthetic precursors to paraherquamide A. (C) 2001 Elsevier Science Ltd. All rights reserved.
Phosphonopeptide K-26 biosynthetic intermediates in Astrosporangium hypotensionis
作者:Ioanna Ntai、Vanessa V. Phelan、Brian O. Bachmann
DOI:10.1039/b611768f
日期:——
Precursors and advanced intermediates for phosphonopeptide K-26 biosynthesis were synthesized and incorporation studies in Astrosporangium hypotensionis suggest a new mechanism of C–P bond formation in aromatic phosphonates.
A Simple and Economical Method for the Production of <sup>13</sup>C,<sup>18</sup>O-Labeled Fmoc-Amino Acids with High Levels of Enrichment: Applications to Isotope-Edited IR Studies of Proteins
作者:James Marecek、BenBen Song、Scott Brewer、Jenifer Belyea、R. Brian Dyer、Daniel P. Raleigh
DOI:10.1021/ol701913p
日期:2007.11.1
Isotope-edited IR of proteins has generated considerable interest. Double labeling with C-13 and O-18 with high levels of isotopic enrichment is required for residue-specific resolution. Current methods for the preparation of doubly labeled amino acids give modest O-18 enrichment, limiting the utility of the approach. We report a simple and economical method for preparing C-13,O-18-doubly labeled N-(9-fluorenylmethoxycarbonyl)-amino acids with high levels of enrichment for residues that do not require acid-labile side-chain protecting groups.
PARRY, RONALD J.;LIN, MING-TEH;WALKER, ALAN E.;MHASKAR, SUNIL, J. AMER. CHEM. SOC., 113,(1991) N, C. 1849-1850
作者:PARRY, RONALD J.、LIN, MING-TEH、WALKER, ALAN E.、MHASKAR, SUNIL
DOI:——
日期:——
IR Study of Cross-Strand Coupling in a β-Hairpin Peptide Using Isotopic Labels
作者:Vladimír Setnička、Rong Huang、Catherine L. Thomas、Marcus A. Etienne、Jan Kubelka、Robert P. Hammer、Timothy A. Keiderling
DOI:10.1021/ja043007f
日期:2005.4.1
Model beta-hairpin peptides can be used to develop understanding of fundamental elements of beta-sheet secondary structure formation and stability. We have studied two 13C-labeled variants of a beta-hairpin peptide modified from a design originally proposed by Gellman: Arg-Tyr-Val-Glu-Val-Aib-Gly-Lys-Lys-Ile-Leu-Gln. (In this peptide, the two italicized residues form a beta-turn, while 13C-labels are on the amide C=O of Val3, Lys8 in HBG-L and Val3, Ile10 in HBG-S.) Both these peptides are labeled on opposite strands of the hairpin, but differ in the labeling pattern. One (HBG-L) forms a large (14-atom) H-bonded ring of labeled C=Os, while the other (HBG-S) forms a small (10-atom) H-bonded ring. These impact the amide I infrared spectra, with HBG-L having a 13C frequency and intensity higher than that of HBG-S, in good agreement with our spectral simulations based on quantum mechanically derived force fields. The thermal behavior of both peptides yields a broad thermal transition and lacks an isosbestic point. The 13C band for HBG-L has the largest intensity change with temperature, distinct from the 12C change and the HBG-S 13C change.
Studies on the biosynthesis of paraherquamide. Construction of the amino acid framework
作者:Emily M Stocking、Juan F Sanz-Cervera、Clifford J Unkefer、Robert M Williams
DOI:10.1016/s0040-4020(01)00449-5
日期:2001.6
It has been previously established in this laboratory that the beta -methyl-beta -hydroxyproline moiety of the potent anthelmintic agent paraherquamide A, is biosynthetically derived from L-isoleucine. The downstream events from L-Ile to paraherquamide A have now been investigated. The synthesis of [1-(13)C]-labeled L-beta -methylproline is described by means of a Hoffman-Loeffler-Freytag reaction sequence from [1-(13)C]-L-Ile. This amino acid is shown to be a direct biosynthetic precursor to paraherquamide A by feeding and incorporation experiments in growing cultures of Penicillum fellutanum. Three tryptophan-containing dipeptides of L-beta -methylproline have been constructed: [(13)C(2)]-2-(l,1-dimethyl-2-propenyl)-L-tryptophanyl-3(S)-methyl-L-proline [(13)C(2)]-3(S)-methyl-L-prolyl-2-(l,1-dimethyl-2-propenyl)-L-tryptophan and [(13)C(2)]-cyclo-2-(l,1-dimethyl-2-propenyl)-L-tryptophan-3(S)-methyl-L-proline. [alpha-(15)N, 1-(13)C]-2-(1,1-Dimethyl-2-propenyl)-L-tryptophan was also prepared but none of these substances were found to serve as biosynthetic precursors to paraherquamide A. (C) 2001 Elsevier Science Ltd. All rights reserved.