Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:2.5.1.47 (
cysteine synthase
)
625
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In the present study, we successfully cloned a 21-kb DNA fragment containing a d-cycloserine (DCS) biosynthetic gene cluster from a DCS-producing Streptomyces lavendulae strain, ATCC 11924. The putative gene cluster consists of 10 open reading frames (ORFs), designated dcsA to dcsJ. This cluster includes two ORFs encoding D-alanyl-D-alanine ligase (dcsI) and a putative membrane protein (dcsJ) as the self-resistance determinants of the producer organism, indicated by our previous work. When the 10 ORFs were introduced into DCS-nonproducing Streptomyces lividans 66 as a heterologous host cell, the transformant acquired DCS productivity. This reveals that the introduced genes are responsible for the biosynthesis of DCS. As anticipated, the disruption of dcsG, seen in the DCS biosynthetic gene cluster, made it possible for the strain ATCC 11924 to lose its DCS production. We here propose the DCS biosynthetic pathway. First, L-serine is O acetylated by a dcsE-encoded enzyme homologous to homoserine O-acetyltransferase. Second, O-acetyl-L-serine accepts hydroxyurea via an
O-acetylserine sulfhydrylase
homolog (dcsD product) and forms O-ureido-L-serine. The hydroxyurea must be supplied by the catalysis of a dcsB-encoded
arginase
homolog using the L-arginine derivative, N(G)-hydroxy-L-arginine. The resulting O-ureido-L-serine is then racemized to O-ureido-D-serine by a homolog of diaminopimelate epimerase. Finally, O-ureido-D-serine is cyclized to form DCS with the release of ammonia and carbon dioxide. The cyclization must be done by the dcsG or dcsH product, which belongs to the ATP-grasp fold family of protein.
...
PMID:Molecular cloning and heterologous expression of a biosynthetic gene cluster for the antitubercular agent D-cycloserine produced by Streptomyces lavendulae. 2008 63
Salinity is one of the abiotic factors that most affect crop growth and production. This study focused on the effect of high salinity on the endogenous levels of the signaling molecules hydrogen sulfite (H
2
S) and nitric oxide (NO) in Nicotiana tabacum leaves and the extent of these for the biochemically-driven plant tolerance to such abiotic stress. The NaCl treatment for 10days led to an expressive augment of H
2
S and NO levels. This increase was correlated with the raise of l-Cys and l-Arg and the induction of l-cysteine desulfhydrase, cyanoalanine synthase,
cysteine synthase
, nitrate reductase and
arginase
, enzymes known to be involved in the biosynthesis of H
2
S or NO. The enzymatic antioxidant system (superoxide dismutase and catalase activity) was boosted and the non-enzymatic antioxidant glutathione was intensively oxidized in leaves upon stress allowing plants to cope with oxidative stress. Lower stomatal conductance was observed in stressed plants in comparison with control ones. Moreover, the high activity of antioxidant enzymes and high rate of glutathione oxidation following salt stress were considerably decreased upon NO or H
2
S scavenging. Thus, increment in NO and H
2
S levels and their interplay, along with metabolic and physiological changes, contributed to tobacco survival to extreme salinity conditions.
...
PMID:Salinity-induced accumulation of endogenous H
2
S and NO is associated with modulation of the antioxidant and redox defense systems in Nicotiana tabacum L. cv. Havana. 2816 28
