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Sharad Chandrakant Deshmukh, Pinaki Talukdar
We report the stereoselective synthesis of an alkynyl side-chain containing (2S,3R)-α-hydroxy-β-amino acid ((2S,3R)-AHBA) analogues. The Cu(I)-catalyzed reactions of (R)-glyceraldehyde acetonide and dibenzylamine with terminal alkynes provided the corresponding (2S,3R)-α-amino alcohols with good-to-excellent diastereoselectivity. Subsequent chemical transformations provided easy access to the alkynyl side-chain containing (2S,3R)-AHBAs. The utility of the methodology was demonstrated by the stereoselective synthesis of valinoctin A and (2S,3R)-3-amino-2-hydroxydecanoic acid ((2S,3R)-AHDA)...
November 21, 2014: Journal of Organic Chemistry
Rajendra S Rohokale, Dilip D Dhavale
A directed manipulation of the functional groups at C3 and C4 of D-glucose was demonstrated to synthesize naturally occurring (2S,3R)-α-hydroxy-β-aminodecanoic acid (AHDA, 2a) and its enantiomer 2b. The enantiomer of 2a is the N-terminal part of the natural linear pentapeptide microginin, which is used as an antihypertensive agent.
2014: Beilstein Journal of Organic Chemistry
Ronaldo Leal Carneiro, Felipe Augusto Dörr, Fabiane Dörr, Stella Bortoli, Nathalie Delherbe, Mónica Vásquez, Ernani Pinto
Species of Microcystis are the most common bloom-forming cyanobacteria in several countries. Despite extensive studies regarding the production of bioactive cyanopeptides in this genus, there are limited data on isolated strains from Brazil. Three Microcystis sp. strains were isolated from the Salto Grande Reservoir (LTPNA01, 08 and 09) and investigated for the presence of mcy genes, microcystins and other cyanopeptides. Microcystin and microginin production was confirmed in two isolates using high-resolution tandem mass spectrometry after electrospray ionization (ESI-Q-TOF), and the structures of two new microginin congeners were proposed (MG756 Ahda-Val-Leu-Hty-Tyr and MG770 MeAhda-Val-Leu-Hty-Tyr)...
December 2012: FEMS Microbiology Ecology
Shinji Takenaka, Tomomi Sato, Jyun Koshiya, Shuichiro Murakami, Kenji Aoki
The 4-amino-3-hydroxybenzoate-assimilating Bordetella sp. strain 10d produces a deaminase that catalyzes the deamination of 2-amino-5-carboxymuconic 6-semialdehyde. A gene encoding the deaminase, ahdB, was cloned and expressed in Escherichia coli; ahdB is located downstream from the previously reported genes encoding 4-amino-3-hydroxybenzoate 2,3-dioxygenase (ahdA) and a LysR-type regulator. The deduced amino acid sequence of ahdB shows 30-33% identity to those of previously reported 2-aminomuconate deaminases...
September 2009: FEMS Microbiology Letters
Alain Wunsch, Yuni Ahda, Ferya Banaz-Yaşar, Barbara Sonntag, Eberhard Nieschlag, Manuela Simoni, Jörg Gromoll
OBJECTIVE: To characterize novel single-nucleotide polymorphisms (SNPs) in the human FSH receptor (FSHR) promoter region. DESIGN: Retrospective and basic research study. SETTING: University hospital. PATIENTS: Women (202 from Germany and 55 from Indonesia) with male or tubal factor infertility undergoing controlled ovarian stimulation for IVF treatment. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Frequency, distribution, and correlation with clinical data of the SNPs...
August 2005: Fertility and Sterility
Yuni Ahda, Jörg Gromoll, Alain Wunsch, Ketevan Asatiani, Michael Zitzmann, Eberhard Nieschlag, Manuela Simoni
The human follicle-stimulating hormone (FSH) receptor (FSHR) gene possesses single nucleotide polymorphisms (SNP) in exon 10, which influence serum FSH levels in women, but not in men. In the present study we extend our previous investigation and for the first time analyze a novel, common SNP at position -29 of the FSHR core promoter in men. The SNP in codon 680 was analyzed in 438 men with nonobstructive azoospermia and in 304 controls. The SNP in codon 307 and at position -29 was analyzed in 345 men with nonobstructive azoospermia and 186 controls...
July 2005: Journal of Andrology
Shuichiro Murakami, Yoshimitsu Sawami, Shinji Takenaka, Kenji Aoki
Bordetella sp. 10d produces a novel dioxygenase catalyzing the meta-cleavage of 4-amino-3-hydroxybenzoic acid, 4-amino-3-hydroxybenzoate 2,3-dioxygenase (4A3HBA23D). A gene encoding 4A3HBA23D was cloned and named ahdA. The deduced amino acid sequence of ahdA showed 29.2-24.2% identities to those of prokaryotic and eukaryotic 3-hydoxybenzoate 3,4-dioxygenases in reported meta-cleavage dioxygenases. However, no identities were observed in the amino-terminal sequences of the first 29 amino acid residues. An ORF was found downstream of ahdA...
February 6, 2004: Biochemical and Biophysical Research Communications
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