Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:83209-65-8 (HC-toxin)
 51 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study of the conformational parameters of HC-toxin and its diacetyl derivative in chloroform solution has been carried out. Two-dimensional NMR spectroscopy and the nuclear Overhauser effect have been used in order to determine connectivities (assignments and sequence) and approximate torsion angles and interproton distances. The results are consistent with a bis-gamma-turn conformation previously reported for dihydrochlamydocin. Model building based upon NMR data supports a D configuration for Ala2 and Pro4 residues.
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PMID:The backbone and side chain conformations of the cyclic tetrapeptide HC-toxin. 686 Mar 26

HC-toxin, cyclo(D-Pro-L-Ala-D-Ala-L-Aeo), where Aeo stands for 2-amino-9,10-epoxi-8-oxodecanoic acid, is a potent inhibitor of histone deacetylase. Previous molecular genetic studies indicated that HC-toxin biosynthesis requires a dedicated fatty acid synthase. The incorporation of [13C]acetate into HC-toxin was studied using NMR. The pattern of incorporation of 13C was consistent with the carbons of Aeo being derived from head-to-tail condensation of acetate.
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PMID:13C labeling indicates that the epoxide-containing amino acid of HC-toxin is biosynthesized by head-to-tail condensation of acetate. 991 3

The known metabolite, enniatin B, and a cyclic tetrapeptide, JM47, which is a new natural product, were extracted from brown rice cultures of a marine fungus, identified as a Fusarium species, isolated from the marine alga Codium fragile. NMR studies, including 15N HMQC and 15N HMBC, established the structure of JM47 as cyclo(Ala-Ala-Aoh-Pro), where Aoh is the amino acid, (2S,9S)-2-amino-8-oxo-9-hydroxydecanoic acid. The absolute stereochemistry of the Aoh side chain carbinol centre was determined using Mosher ester methodology. Analysis of NOESY data assisted by molecular modelling revealed an alternating L-, D-, L-, D-configuration for the tetrapeptide core. The absolute stereochemistry of the core was determined by acidic hydrolysis and chiral TLC analysis of the proline residue. JM47 belongs to the HC-toxin family of cyclic tetrapeptides which possess a 2-amino-8-oxo-9,10-epoxydecanoic acid residue in place of the Aoh unit. This is the first report of an analogue of HC-toxin from a marine Fusarium species.
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PMID:JM47, a cyclic tetrapeptide HC-toxin analogue from a marine Fusarium species. 1198 49

Naturally occurring cyclic tetrapeptides (CTPs) such as tentoxin (Halloin et al., Plant Physiol 1970, 45, 310-314; Saad, Phytopathology 1970, 60, 415-418), ampicidin (Darkin-Rattray, Proc Natl Acad Sci USA 1996, 93, 13143-13147), HC-toxin (Walton, Proc Natl Acad Sci USA 1987, 84, 8444-8447), and trapoxin (Yoshida and Sugita, Jpn J Cancer Res 1992, 83, 324-328; Itazaki et al., J Antibiot (Tokyo) 1990, 43, 1524-1532) have a wide range of biological activity and potential use ranging from herbicides (Walton, Proc Natl Acad Sci USA 1987, 84, 8444-8447; Judson, J Agric Food Chem 1987, 35, 451-456) to therapeutics (Loiseau, Biopolymers 2003, 69, 363-385) for malaria (Darkin-Rattray, Proc Natl Acad Sci USA 1996, 93, 13143-13147) and cancer (Yoshida and Sugita, Jpn J Cancer Res 1992, 83, 324-328). To elucidate scaffolds that have few low-energy conformations and could serve as semirigid reverse-turn mimetics, the flexibility of CTPs was determined computationally. Four analogs of cyclic tetraproline c[Pro-pro-Pro-pro] with alternating L- and D-prolines, namely c[pro-Pro-pro-NMe-Ala], c[pip-Pro-pip-Pro], c[pro-Pip-pro-Pro], and c[Ala-Pro-pip-Pro] were synthesized and characterized by NOESY NMR. Both molecular mechanics and Density Functional Theory quantum calculations found these head-to-tail CTPs to be constrained to one or two relatively stable conformations. NMR structures, while not always yielding the same lowest energy conformation as expected by in silico predictions, confirmed only one or two highly populated solution conformations for all four peptides examined. c[pro-Pro-pro-NMe-Ala] was shown to have a single all trans-amide bond conformation from both in silico predictions and NMR characterization, and to be a reverse-turn mimetic by overlapping four Calpha-Cbeta bonds with those for approximately 6.5% (Tran, J Comput Aided Mol Des 2005, 19, 551-566) of reverse-turns in the Protein Data Bank PDB with a RMSD of 0.57 A.
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PMID:c[D-pro-Pro-D-pro-N-methyl-Ala] adopts a rigid conformation that serves as a scaffold to mimic reverse-turns. 1794 Oct 3