Journal
BIOCHEMICAL JOURNAL
Volume 394, Issue -, Pages 657-664Publisher
PORTLAND PRESS LTD
DOI: 10.1042/BJ20051311
Keywords
cysteate dissimilation; desulphonation; pyridoxal 5 '-phosphate; sequence comparisons; sulphite exporter
Categories
Ask authors/readers for more resources
Quantitative utilization of L-cysteate (2-amino-3-sulphopropionate) as the sole source of carbon and energy for growth of the aerobic, marine bacterium Silicibacter pomeroyi DSS-3(T) was observed. The sulphonate moiety was recovered in the medium largely as sulphite, and the appropriate amount of the ammonium ion was also observed. Genes [suyAB (3-sulpholactate sulpholyase)] encoding the known desulphonation reaction in cysteate degradation were absent from the genome, but a homologue of a putative sulphate exporter gene (suyZ) was found, and its neighbour, annotated as a D-cysteine desulphhydrase, was postulated to encode pyridoxal 5'-phosphate-coupled L-cysteate sulpho-lyase (CuyA), a novel enzyme. Inducible CuyA was detected in cysteate-grown cells. The enzyme released equimolar pyruvate, sulphite and the ammonium ion from L-cysteate and was purified to homogeneity by anion-exchange, hydrophobic-interaction and gel-filtration chromatography. The N-terminal amino acid sequence of this 39-kDa subunit confirmed the identification of the cuyA gene. The native enzyme was soluble and homomultimeric. The K-m-value for L-Cysteate was high (11.7 mM) and the enzyme also catalysed the D-Cysteine desulphhydrase reaction. The gene cuyZ, encoding the putative sulphite exporter, was co-transcribed with cuyA. Sulphite was exported despite the presence of a ferricyanide-coupled sulphite dehydrogenase. CuyA was found in many bacteria that utilize cysteate.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available