|Gene:||cynS||Accession Numbers: EG10175 (EcoCyc), b0340, ECK0337|
Synonyms: cnt, cyaN
Cyanase is an inducible enzyme in E. coli and was first reported and subsequently studied in E. coli B [Taussig60, Anderson80]. The cyanase operon may have evolved to function in detoxification/decomposition of cyanate arising from intra- and extracellular activities [Anderson90a].
It was shown that bicarbonate (HCO3-) is a substrate of the enzyme, and that water does not participate as a substrate [Johnson87]. The initial product carbamate is unstable and spontaneously decomposes to ammonia and carbon dioxide [Anderson80]. The enzyme shows competitive substrate inhibition by both substrates [Anderson86].
The native enzyme from E. coli B has a molecular weight of ca. 150 kDa and thus appears to be a homodecamer in solution [Anderson80]. A crystal structure of cyanase was solved at 1.65 Å resolution; it showed a homodecamer composed of five dimers. The structure allowed identification of the active site, which is located between dimers and is comprised of residues from four adjacent subunits [Walsh00].
The free sulfhydryl group of the single cysteine residue is not required for catalytic activity, but plays a role in stabilizing the decameric structure [Anderson88d, Anderson94]. The single histidine residue is also required for the stability of the decamer and contributes to its catalytic properties [Anderson94, Anderson94a].
|Map Position: [358,713 -> 359,183] (7.73 centisomes, 28°)||Length: 471 bp / 156 aa|
Molecular Weight of Polypeptide: 17.049 kD (from nucleotide sequence), 16.5 kD (experimental) [Sung87 ]
Molecular Weight of Multimer cyanase: 150 kD (experimental) [Anderson80]
Unification Links: ASAP:ABE-0001173 , CGSC:15267 , DIP:DIP-9365N , EchoBASE:EB0172 , EcoGene:EG10175 , EcoliWiki:b0340 , ModBase:P00816 , OU-Microarray:b0340 , PortEco:cynS , PR:PRO_000022366 , Pride:P00816 , Protein Model Portal:P00816 , RefSeq:NP_414874 , RegulonDB:EG10175 , SMR:P00816 , String:511145.b0340 , UniProt:P00816
Relationship Links: InterPro:IN-FAMILY:IPR003712 , InterPro:IN-FAMILY:IPR008076 , InterPro:IN-FAMILY:IPR010982 , PDB:Structure:1DW9 , PDB:Structure:1DWK , PDB:Structure:2IU7 , PDB:Structure:2IUO , PDB:Structure:2IV1 , PDB:Structure:2IVB , PDB:Structure:2IVG , PDB:Structure:2IVQ , Pfam:IN-FAMILY:PF02560 , Prints:IN-FAMILY:PR01693
|Biological Process:||GO:0009440 - cyanate catabolic process
GO:0009439 - cyanate metabolic process [GOA06, GOA01]
|Molecular Function:||GO:0008824 - cyanate hydratase activity
[GOA06, GOA01a, GOA01, Anderson87]
GO:0003677 - DNA binding [GOA01]
GO:0016829 - lyase activity [UniProtGOA11]
|Cellular Component:||GO:0005737 - cytoplasm
GO:0005829 - cytosol [DiazMejia09]
|MultiFun Terms:||cell processes → protection → detoxification|
|metabolism → central intermediary metabolism → cyanate catabolism|
|metabolism → metabolism of other compounds → nitrogen metabolism|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB Lennox||Yes||37||Aerobic||7||Yes [Baba06, Comment 1]|
|M9 medium with 1% glycerol||Yes||37||Aerobic||7.2||0.35||Yes [Joyce06, Comment 2]|
|MOPS medium with 0.4% glucose||Yes||37||Aerobic||7.2||0.22||Yes [Baba06, Comment 1] |
Yes [Feist07, Comment 3]
Enzymatic reaction of: cyanase
Synonyms: cyanate hydrolase, cyanate C-N-lyase, cyanate aminohydrolase, cyanate lyase, cyanate hydratase
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
The reaction is physiologically favored in the direction shown.
In Pathways: cyanate degradation
The enzyme was initially purified from E. coli B [Anderson80, Chin83, Anderson86]. A number of kinetic and physical properties of the K-12 and B enzymes were compared and found to be identical [Sung87a].
Cyanase is inhibited by dianions such as oxalate and malonate [Anderson87].
Inhibitors (Competitive): oxalate [Anderson87, Comment 4] , formate [Little87, Comment 5] , nitrite [Little87, Comment 5] , nitrate [Little87, Comment 6] , bromide [Little87, Comment 5] , chloride [Little87, Comment 5] , acetate [Little87, Comment 7] , azide [Little87, Comment 8] , cyanate [Anderson86] , hydrogen carbonate [Anderson86]
10/20/97 Gene b0340 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10175; confirmed by SwissProt match.
Anderson87: Anderson PM, Johnson WV, Endrizzi JA, Little RM, Korte JJ (1987). "Interaction of mono- and dianions with cyanase: evidence for apparent half-site binding." Biochemistry 26(13);3938-43. PMID: 3651424
Anderson88d: Anderson PM, Johnson WV, Korte JJ, Xiong XF, Sung YC, Fuchs JA (1988). "Reversible dissociation of active octamer of cyanase to inactive dimer promoted by alteration of the sulfhydryl group." J Biol Chem 263(12);5674-80. PMID: 3128546
Anderson94: Anderson PM, Korte JJ, Holcomb TA, Cho YG, Son CM, Sung YC (1994). "Formation of intersubunit disulfide bonds and properties of the single histidine and cysteine residues in each subunit relative to the decameric structure of cyanase." J Biol Chem 269(21);15036-45. PMID: 8195141
Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909
Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394
Kozliak94: Kozliak EI, Guilloton MB, Gerami-Nejad M, Fuchs JA, Anderson PM (1994). "Expression of proteins encoded by the Escherichia coli cyn operon: carbon dioxide-enhanced degradation of carbonic anhydrase." J Bacteriol 176(18);5711-7. PMID: 8083164
Little87: Little RM, Anderson PM (1987). "Structural properties of cyanase. Denaturation, renaturation, and role of sulfhydryls and oligomeric structure in catalytic activity." J Biol Chem 1987;262(21);10120-6. PMID: 3301828
Sung87a: Sung YC, Anderson PM, Fuchs JA (1987). "Characterization of high-level expression and sequencing of the Escherichia coli K-12 cynS gene encoding cyanase." J Bacteriol 169(11);5224-30. PMID: 2822670
Walsh00: Walsh MA, Otwinowski Z, Perrakis A, Anderson PM, Joachimiak A (2000). "Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site." Structure 8(5);505-14. PMID: 10801492
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