Escherichia coli K-12 substr. MG1655 Enzyme: cysteine synthase B

Gene: cysM Accession Numbers: EG10193 (EcoCyc), b2421, ECK2416

Regulation Summary Diagram: ?

Regulation summary diagram for cysM

Subunit composition of cysteine synthase B = [CysM]2

Cysteine synthase B is one of two isozymes in E. coli that catalyze the formation of L-cysteine from O-acetyl-L-serine and sulfide [Neidhardt96]. Unlike cysteine synthase A, cysteine synthase B does not form a complex with serine acetyltransferase [Zhao06a]. Both isozymes can also catalyze the reverse reaction, mobilizing sulfur from cysteine and providing it for Fe-S cluster synthesis in vitro. This reaction can be driven by removing the sulfide product or by dithiothreitol adding to the aminoacrylate [Flint96].

Cysteine synthase B can also use thiosulfate in place of sulfide, producing S-sulfocysteine [Maier03]. The broad substrate specificity of cysteine synthase was exploited for the synthesis of unnatural L-α-amino acids [Maier03]. Initial synthesis rates of nonproteinaceous amino acids have been determined [Zhao06a].

Analyses with gene-disrupted mutants recently confirm that Cysteine synthase B also exhibits cysteine desulfhydrase activity (CD) in E. coli. In addition to CysM, the gene disruption for each of the MetC, TnaA, CysK and MalY proteins significantly decreases the CD activity and is effective for overproduction of L-cysteine [Awano03, Awano05].

Crystal structures of CysM have been solved at 2.1 and 2.7 Å resolution [Claus05].

Gene Citations: [Sirko90, Hryniewicz90]

Locations: cytosol

Map Position: [2,536,694 <- 2,537,605] (54.67 centisomes, 197°)
Length: 912 bp / 303 aa

Molecular Weight of Polypeptide: 32.664 kD (from nucleotide sequence)

Molecular Weight of Multimer: 64 kD (experimental) [Zhao06a]

Isozyme Sequence Similarity:
O-acetylserine sulfhydrylase A: YES

Unification Links: ASAP:ABE-0007982 , CGSC:17722 , DIP:DIP-9383N , EchoBASE:EB0190 , EcoGene:EG10193 , EcoliWiki:b2421 , Mint:MINT-1300981 , ModBase:P16703 , OU-Microarray:b2421 , PortEco:cysM , PR:PRO_000022383 , Protein Model Portal:P16703 , RefSeq:NP_416916 , RegulonDB:EG10193 , SMR:P16703 , String:511145.b2421 , UniProt:P16703

Relationship Links: InterPro:IN-FAMILY:IPR001216 , InterPro:IN-FAMILY:IPR001926 , InterPro:IN-FAMILY:IPR005856 , InterPro:IN-FAMILY:IPR005858 , PDB:Structure:2BHS , PDB:Structure:2BHT , PDB:Structure:2V03 , Pfam:IN-FAMILY:PF00291 , Prosite:IN-FAMILY:PS00901

In Paralogous Gene Group: 362 (8 members)

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for cysM

GO Terms:

Biological Process: GO:0006535 - cysteine biosynthetic process from serine Inferred from experiment Inferred by computational analysis [GOA01, Zhao06a]
GO:0008652 - cellular amino acid biosynthetic process Inferred by computational analysis [UniProtGOA11]
GO:0019344 - cysteine biosynthetic process Inferred by computational analysis [UniProtGOA12, UniProtGOA11]
Molecular Function: GO:0004124 - cysteine synthase activity Inferred from experiment Inferred by computational analysis [GOA01a, GOA01, Zhao06a]
GO:0080146 - L-cysteine desulfhydrase activity Inferred from experiment [Awano05]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11]
GO:0030170 - pyridoxal phosphate binding Inferred by computational analysis [Gaudet10]
Cellular Component: GO:0005737 - cytoplasm Inferred by computational analysis [Gaudet10]
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]

MultiFun Terms: metabolism biosynthesis of building blocks amino acids cysteine

Essentiality data for cysM knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Curated 21-Mar-2006 by Keseler I , SRI International
Last-Curated ? 22-Mar-2007 by Shearer A , SRI International
Reviewed 05-Apr-2010 by Sarker M

Enzymatic reaction of: cysteine synthase

Synonyms: O-acetylserine (thiol)-lyase B, O-acetylserine sulfhydrylase B, CSASE B, O3-acetyl-L-serine acetate-lyase (adding hydrogen-sulfide), OASS-B

EC Number:

O-acetyl-L-serine + hydrogen sulfide <=> L-cysteine + acetate + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

Alternative Substrates for hydrogen sulfide: thiosulfate

In Pathways: superpathway of sulfate assimilation and cysteine biosynthesis , L-cysteine biosynthesis I

The reaction follows a ping-pong bi bi mechanism [Zhao06a].

Cofactors or Prosthetic Groups: pyridoxal 5'-phosphate

Kinetic Parameters:

Km (μM)

pH(opt): 7.2-9 [Zhao06a]

Enzymatic reaction of: L-cysteine desulfhydrase (cysteine synthase B)

L-cysteine <=> 2-aminoprop-2-enoate + hydrogen sulfide + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

In Pathways: L-cysteine degradation II

Sequence Features

Protein sequence of CysM with features indicated

Feature Class Location Citations Comment
N6-pyridoxal-phosphate-Lys-Modification 41
UniProt: N6-(pyridoxal phosphate)lysine.
Amino-Acid-Sites-That-Bind 71
[Claus05, UniProt15]
UniProt: Pyridoxal phosphate.
Protein-Segment 174 -> 178
UniProt: Pyridoxal phosphate binding; Sequence Annotation Type: region of interest;
Amino-Acid-Sites-That-Bind 255
[Claus05, UniProt15]
UniProt: Pyridoxal phosphate.

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b2421 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10193; confirmed by SwissProt match.


Awano03: Awano N, Wada M, Kohdoh A, Oikawa T, Takagi H, Nakamori S (2003). "Effect of cysteine desulfhydrase gene disruption on L-cysteine overproduction in Escherichia coli." Appl Microbiol Biotechnol 62(2-3);239-43. PMID: 12883870

Awano05: Awano N, Wada M, Mori H, Nakamori S, Takagi H (2005). "Identification and functional analysis of Escherichia coli cysteine desulfhydrases." Appl Environ Microbiol 71(7);4149-52. PMID: 16000837

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

Claus05: Claus MT, Zocher GE, Maier TH, Schulz GE (2005). "Structure of the O-acetylserine sulfhydrylase isoenzyme CysM from Escherichia coli." Biochemistry 44(24);8620-6. PMID: 15952768

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

Flint96: Flint DH, Tuminello JF, Miller TJ (1996). "Studies on the synthesis of the Fe-S cluster of dihydroxy-acid dehydratase in escherichia coli crude extract. Isolation of O-acetylserine sulfhydrylases A and B and beta-cystathionase based on their ability to mobilize sulfur from cysteine and to participate in Fe-S cluster synthesis." J Biol Chem 271(27);16053-67. PMID: 8663055

Gaudet10: Gaudet P, Livstone M, Thomas P (2010). "Annotation inferences using phylogenetic trees." PMID: 19578431

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

Hryniewicz90: Hryniewicz M, Sirko A, Palucha A, Bock A, Hulanicka D (1990). "Sulfate and thiosulfate transport in Escherichia coli K-12: identification of a gene encoding a novel protein involved in thiosulfate binding." J Bacteriol 1990;172(6);3358-66. PMID: 2188959

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

Maier03: Maier TH (2003). "Semisynthetic production of unnatural L-alpha-amino acids by metabolic engineering of the cysteine-biosynthetic pathway." Nat Biotechnol 21(4);422-7. PMID: 12640465

Neidhardt96: Neidhardt FC, Curtiss III R, Ingraham JL, Lin ECC, Low Jr KB, Magasanik B, Reznikoff WS, Riley M, Schaechter M, Umbarger HE "Escherichia coli and Salmonella, Cellular and Molecular Biology, Second Edition." American Society for Microbiology, Washington, D.C., 1996.

Sirko90: Sirko A, Hryniewicz M, Hulanicka D, Bock A (1990). "Sulfate and thiosulfate transport in Escherichia coli K-12: nucleotide sequence and expression of the cysTWAM gene cluster." J Bacteriol 1990;172(6);3351-7. PMID: 2188958

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt15: UniProt Consortium (2015). "UniProt version 2015-01 released on 2015-01-16 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA12: UniProt-GOA (2012). "Gene Ontology annotation based on UniPathway vocabulary mapping."

Zhao06a: Zhao C, Kumada Y, Imanaka H, Imamura K, Nakanishi K (2006). "Cloning, overexpression, purification, and characterization of O-acetylserine sulfhydrylase-B from Escherichia coli." Protein Expr Purif 47(2):607-13. PMID: 16546401

Other References Related to Gene Regulation

Grudniak11: Grudniak AM, Kurek A, Szarlak J, Wolska KI (2011). "Oleanolic and ursolic acids influence affect the expression of the cysteine regulon and the stress response in Escherichia coli." Curr Microbiol 62(4);1331-6. PMID: 21221969

Lochowska01: Lochowska A, Iwanicka-Nowicka R, Plochocka D, Hryniewicz MM (2001). "Functional dissection of the LysR-type CysB transcriptional regulator. Regions important for DNA binding, inducer response, oligomerization, and positive control." J Biol Chem 276(3);2098-107. PMID: 11038360

Lochowska04: Lochowska A, Iwanicka-Nowicka R, Zaim J, Witkowska-Zimny M, Bolewska K, Hryniewicz MM (2004). "Identification of activating region (AR) of Escherichia coli LysR-type transcription factor CysB and CysB contact site on RNA polymerase alpha subunit at the cysP promoter." Mol Microbiol 53(3);791-806. PMID: 15255893

Otsuka96: Otsuka J, Watanabe H, Mori KT (1996). "Evolution of transcriptional regulation system through promiscuous coupling of regulatory proteins with operons; suggestion from protein sequence similarities in Escherichia coli." J Theor Biol 1996;178(2);183-204. PMID: 8729576

WhiteZiegler07: White-Ziegler CA, Malhowski AJ, Young S (2007). "Human body temperature (37degrees C) increases the expression of iron, carbohydrate, and amino acid utilization genes in Escherichia coli K-12." J Bacteriol 189(15);5429-40. PMID: 17526711

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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