Catalyzes the desulfonation and deamination of L-cysteate, yielding pyruvate, sulphite and ammonium. Is involved in a L-cysteate degradation pathway that allows Silicibacter pomeroyi to grow on L-cysteate as the sole source of carbon and energy. •

MHLARYPRRFIAHLPTPLERLDRLTAELGGPEIWIKRDDCTGLSTGGNKTRKLEFLMAEA ELQGADMVMTQGATQSNHARQTAAFAAKLGMDCHILLEDRTGSNNANYNNNGNVLLDHLH GATTEKRPGSGLDMNAEMEKVAEKFRADGRKVYTIPGGGSNPTGALGYVNCAFEMLNQFN ERGLKVDHIVHATGSAGTQAGLITGLQAMNAQIPLLGIGVRAPKPKQEENVYNLACATAE KLGCPGVVAREDVVANTDYVGEGYGIPTESGLEAIRMFAELEAILLDPVYSAKGAAGFID LIRKGHFKKGERVVFLHTGGAVALFGYDNAFDYSGRWVA344

	PMID	Title & Author	Abstract	Year
0	19581363	Genome sequence of Silicibacter pomeroyi reveals adaptations to the marine environment. Denger K, Mayer J, Buhmann M, Weinitschke S, Smits TH, Cook AM.	Data from the genome sequence of the aerobic, marine bacterium Roseovarius nubinhibens ISM were interpreted such that 3-sulfolactate would be degraded as a sole source of carbon and energy for growth via a novel bifurcated pathway including two known desulfonative enzymes, sulfoacetaldehyde acetyltransferase (EC 2.3.3.15) (Xsc) and cysteate sulfo-lyase (EC 4.4.1.25) (CuyA). Strain ISM utilized sulfolactate quantitatively with stoichiometric excretion of the sulfonate sulfur as sulfate. A combination of enzyme assays, analytical chemistry, enzyme purification, peptide mass fingerprinting, and reverse transcription-PCR data supported the presence of an inducible, tripartite sulfolactate uptake system (SlcHFG), and a membrane-bound sulfolactate dehydrogenase (SlcD) which generated 3-sulfopyruvate, the point of bifurcation. 3-Sulfopyruvate was in part decarboxylated by 3-sulfopyruvate decarboxylase (EC 4.1.1.79) (ComDE), which was purified. The sulfoacetaldehyde that was formed was desulfonated by Xsc, which was identified, and the acetyl phosphate was converted to acetyl-coenzyme A by phosphate acetyltransferase (Pta). The other portion of the 3-sulfopyruvate was transaminated to (S)-cysteate, which was desulfonated by CuyA, which was identified. The sulfite that was formed was presumably exported by CuyZ (TC 9.B.7.1.1 in the transport classification system), and a periplasmic sulfite dehydrogenase is presumed. Bioinformatic analyses indicated that transporter SlcHFG is rare but that SlcD is involved in three different combinations of pathways, the bifurcated pathway shown here, via CuyA alone, and via Xsc alone. This novel pathway involves ComDE in biodegradation, whereas it was discovered in the biosynthesis of coenzyme M. The different pathways of desulfonation of sulfolactate presumably represent final steps in the biodegradation of sulfoquinovose (and exudates derived from it) in marine and aquatic environments.	2009
1	16302849	L-cysteate sulpho-lyase, a widespread pyridoxal 5'-phosphate-coupled desulphonative enzyme purified from Silicibacter pomeroyi DSS-3(T). Denger K, Smits TH, Cook AM.	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 sulpho-lyase)] 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.	2006

Denger, K., Mayer, J., Buhmann, M., Weinitschke, S., Smits, T.H., and Cook, A.M. (2009) Bifurcated degradative pathway of 3‐sulfolactate in Roseovarius nubinhibens ISM via sulfoacetaldehyde acetyltransferase and (S)‐cysteate sulfolyase. J Bacteriol 191: 5648–5656. Denger K , Smits T ? , Cook A . L-Cysteate sulpho-lyase, a widespread pyridoxal 5′-phosphate-coupled desulphonative enzyme purified from , Silicibacter pomeroyi , DSS-3 , T[J]. Biochemical Journal, 2006, 394(3):657-664.