<i>O</i>
            ‐Acetylserine Sulfhydrylase

Tai, Chia-Hui; Cook, Paul F.

doi:10.1002/9780470123201.ch5

Cited by 24 publications

(17 citation statements)

References 75 publications

(61 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The apparent K M value for OAS (0.6 mM) and cysteine (0.7 mM) indicated that the enzyme shows similar affinity for both substrates. The enzyme probably forms an α-aminoacrylate intermediate, as has been reported for other OASS (Tai and Cook 2000). The α-aminoacrylate that resides quite stably in the enzyme is then released by nucleophiles such as sulfide or DTT.…”

Section: Discussionmentioning

confidence: 84%

CysK from Lactobacillus casei encodes a protein with O-acetylserine sulfhydrylase and cysteine desulfurization activity

Bogićević

Berthoud

Portmann

et al. 2011

Appl Microbiol Biotechnol

View full text Add to dashboard Cite

A gene encoding an O-acetyl-L-serine sulfhydrylase (cysK) was cloned from Lactobacillus casei FAM18110 and expressed in Escherichia coli. The purified recombinant enzyme synthesized cysteine from sulfide and O-acetyl-L-serine at pH 5.5 and pH 7.4. At pH 7.4, the apparent K(M) for O-acetyl-L-serine (OAS) and sulfide were 0.6 and 6.7 mM, respectively. Furthermore, the enzyme showed cysteine desulfurization activity in the presence of dithiothreitol at pH 7.5, but not at pH 5.5. The apparent K(M) for L-cysteine was 0.7 mM. The synthesis of cystathionine from homocysteine and serine or OAS was not observed. When expressed in a cysMK mutant of Escherichia coli, the cloned gene complemented the cysteine auxotrophy of the mutant. These findings suggested that the gene product is mainly involved in cysteine biosynthesis in L. casei. Quantitative real-time PCR and a mass spectrometric assay based on selected reaction monitoring demonstrated that L. casei FAM18110 is constitutively overexpressing cysK.

show abstract

Section: Discussionmentioning

confidence: 84%

CysK from Lactobacillus casei encodes a protein with O-acetylserine sulfhydrylase and cysteine desulfurization activity

Bogićević

Berthoud

Portmann

et al. 2011

Appl Microbiol Biotechnol

View full text Add to dashboard Cite

show abstract

“…Cook and coworkers have studied the enzyme O-acetylserine sulfhydrylase, which appears to employ an E2-type mechanism. [11, 69–74]…”

Section: Plp Protonation Statementioning

confidence: 99%

Controlling reaction specificity in pyridoxal phosphate enzymes

Toney

2011

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

155

169

View full text Add to dashboard Cite

Pyridoxal 5'-phosphate enzymes are ubiquitous in the nitrogen metabolism of all organisms. They catalyze a wide variety of reactions including racemization, transamination, decarboxylation, elimination, retro-aldol cleavage, Claisen condensation, and others on substrates containing an amino group, most commonly α-amino acids. The wide variety of reactions catalyzed by PLP enzymes is enabled by the ability of the covalent aldimine intermediate formed between substrate and PLP to stabilize carbanionic intermediates at Cα of the substrate. This review attempts to summarize the mechanisms by which reaction specificity can be achieved in PLP enzymes by focusing on three aspects of these reactions: stereoelectronic effects, protonation state of the external aldimine intermediate, and interaction of the carbanionic intermediate with the protein side chains present in the active site.

show abstract

“…In fact, the internal aldimine species disappears with the concomitant formation of bands at 338 and 470 nm (Fig. 3A), attributed to the enolimine and ketoenamine tautomers of the ␣-aminoacrylate Schiff base, by analogy to the spectral properties of this intermediate in other PLP-dependent enzymes catalyzing ␤-elimination/replacement reactions (65)(66)(67). Therefore, the formation of the gem-diamine and the external aldimine is followed by a faster conversion to subsequent reaction intermediates.…”

Section: Cystine Cysteinementioning

confidence: 99%

“…66 and 81 and references therein), O-acetylserine sulfhydrylase (see Ref. 65 and references therein), cystathionine ␤-synthase (see Refs. 82 and 83 and references therein), tryptophan indole-lyase and tyrosine phenol-lyase (see Ref.…”

Section: Cystine Cysteinementioning

confidence: 99%

Sulfur Mobilization in Cyanobacteria

Campanini

Schiaretti

Abbruzzetti

et al. 2006

Journal of Biological Chemistry

View full text Add to dashboard Cite

Sulfur mobilization represents one of the key steps in ubiquitous Fe-S clusters assembly and is performed by a recently characterized set of proteins encompassing cysteine desulfurases, assembly factors, and shuttle proteins. Despite the evolutionary conservation of these proteins, some degree of variability among organisms was observed, which might reflect functional specialization. L-Cyst(e)ine lyase (C-DES), a pyridoxal 5-phosphatedependent enzyme identified in the cyanobacterium Synechocystis, was reported to use preferentially cystine over cysteine with production of cysteine persulfide, pyruvate, and ammonia. In this study, we demonstrate that C-DES sequences are present in all cyanobacterial genomes and constitute a new family of sulfur-mobilizing enzymes, distinct from cysteine desulfurases. The functional properties of C-DES from Synechocystis sp. PCC 6714 were investigated under pre-steady-state and steady-state conditions. Single wavelength and rapid scanning stopped-flow kinetic data indicate that the internal aldimine reacts with cystine forming an external aldimine that rapidly decays to a transient quinonoid species and stable tautomers of the ␣-aminoacrylate Schiff base. In the presence of cysteine, the transient formation of a dipolar species precedes the selective and stable accumulation of the enolimine tautomer of the external aldimine, with no formation of the ␣-aminoacrylate Schiff base under reducing conditions. Effective sulfur mobilization from cystine might represent a mechanism that allows adaptation of cyanobacteria to different environmental conditions and to light-dark cycles.

show abstract

O ‐Acetylserine Sulfhydrylase

Cited by 24 publications

References 75 publications

CysK from Lactobacillus casei encodes a protein with O-acetylserine sulfhydrylase and cysteine desulfurization activity

CysK from Lactobacillus casei encodes a protein with O-acetylserine sulfhydrylase and cysteine desulfurization activity

Controlling reaction specificity in pyridoxal phosphate enzymes

Sulfur Mobilization in Cyanobacteria

Contact Info

Product

Resources

About