Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015

Escherichia coli K-12 substr. MG1655 Enzyme: 7-α-hydroxysteroid dehydrogenase

Gene: hdhA Accession Numbers: EG10425 (EcoCyc), b1619, ECK1614

Synonyms: hsd, hsdH

Regulation Summary Diagram: ?

Regulation summary diagram for hdhA

Subunit composition of 7-α-hydroxysteroid dehydrogenase = [HdhA]4
         7-α-hydroxysteroid dehydrogenase = HdhA

7-α-hydroxysteroid dehydrogenase catalyzes the dehydroxylation of cholic and chenodeoxycholic acids, major human bile acids, yielding 7-oxocholic and 7-oxochenodeoxycholic acids, respectively. The enzyme belongs to the short-chain nonmetalloenzyme-alcohol dehydrogenase protein family. The enzyme shows activity with several substrates having a hydroxyl group at position 7 of the steroid skeleton. NAD+ is required for enzyme activity [Yoshimoto91].

Crystal structures of the enzyme in binary and ternary complexes have been solved. Substrate binding induces a large conformational change at the substrate binding loop and in the C-terminal amino acids. A catalytic mechanism has been proposed [Tanaka96]. Site-directed mutagenesis of proposed catalytic residues confirmed their roles [Tanabe98].

Protein levels of HdhA are increased by osmotic stress under both aerobic and anaerobic conditions [Weber06]. hdhA belongs to the σS regulon [Weber05].

HdhA: "7-α-hydroxysteroid dehydrogenase A" [Yoshimoto93]

Citations: [Tanaka96a, Lelong07]

Locations: cytosol

Map Position: [1,695,297 <- 1,696,064] (36.54 centisomes, 132°)
Length: 768 bp / 255 aa

Molecular Weight of Polypeptide: 26.779 kD (from nucleotide sequence), 28 kD (experimental) [Yoshimoto91 ]

Molecular Weight of Multimer: 120 kD (experimental) [Yoshimoto91]

pI: 4.3 [Yoshimoto91]

Unification Links: ASAP:ABE-0005419 , CGSC:32248 , DIP:DIP-9875N , EchoBASE:EB0420 , EcoGene:EG10425 , EcoliWiki:b1619 , ModBase:P0AET8 , OU-Microarray:b1619 , PortEco:hdhA , PR:PRO_000022872 , Pride:P0AET8 , Protein Model Portal:P0AET8 , RefSeq:NP_416136 , RegulonDB:EG10425 , SMR:P0AET8 , String:511145.b1619 , Swiss-Model:P0AET8 , UniProt:P0AET8

Relationship Links: InterPro:IN-FAMILY:IPR002198 , InterPro:IN-FAMILY:IPR002347 , InterPro:IN-FAMILY:IPR016040 , InterPro:IN-FAMILY:IPR020904 , PDB:Structure:1AHH , PDB:Structure:1AHI , PDB:Structure:1FMC , Pfam:IN-FAMILY:PF00106 , Prints:IN-FAMILY:PR00080 , Prints:IN-FAMILY:PR00081 , Prosite:IN-FAMILY:PS00061

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Biological Process: GO:0030573 - bile acid catabolic process Inferred from experiment Inferred by computational analysis [UniProtGOA11a, Yoshimoto91]
GO:0051289 - protein homotetramerization Inferred from experiment [Yoshimoto91]
GO:0006629 - lipid metabolic process Inferred by computational analysis [UniProtGOA11a]
GO:0008152 - metabolic process Inferred by computational analysis [GOA01a]
GO:0008202 - steroid metabolic process Inferred by computational analysis [UniProtGOA11a]
GO:0016042 - lipid catabolic process Inferred by computational analysis [UniProtGOA11a]
GO:0055114 - oxidation-reduction process Inferred by computational analysis [UniProtGOA11a]
Molecular Function: GO:0008709 - cholate 7-alpha-dehydrogenase activity Inferred from experiment Inferred by computational analysis [GOA01, Yoshimoto91]
GO:0042802 - identical protein binding Inferred from experiment [Yoshimoto91]
GO:0016491 - oxidoreductase activity Inferred by computational analysis [UniProtGOA11a, GOA01a]
Cellular Component: GO:0005829 - cytosol Inferred from experiment Inferred by computational analysis [DiazMejia09, Ishihama08, LopezCampistrou05, Lasserre06]

MultiFun Terms: metabolism central intermediary metabolism unassigned reversible reactions

Essentiality data for hdhA 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]

Last-Curated ? 01-Jul-2014 by Keseler I , SRI International

Enzymatic reaction of: 7-α-hydroxysteroid dehydrogenase

Synonyms: 7-α-hydroxysteroid:NAD+ 7-oxidoreductase, 7α-HSDH

EC Number:

cholate + NAD+ <=> 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oate + NADH + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Alternative Substrates for cholate [Comment 4 ]: taurochenodeoxycholate [Yoshimoto91 ] , chenodeoxycholate [Yoshimoto91 ]

Inhibitors (Unknown Mechanism): Cu2+ [Yoshimoto91] , Zn2+ [Yoshimoto91] , Hg2+ [Yoshimoto91] , nickel sulphate [Yoshimoto91] , cobalt chloride [Yoshimoto91] , ferric chloride [Yoshimoto91] , ferrous chloride [Yoshimoto91] , N-bromosuccinimide [Yoshimoto91] , diethylpyrocarbonate [Yoshimoto91]

Kinetic Parameters:

Km (μM)
kcat (sec-1)
kcat/Km (sec-1 μM-1)
[Macdonald73, BRENDA14]
[Yoshimoto91, BRENDA14]
[Tanabe98, BRENDA14]
[Tanabe98, BRENDA14]

pH(opt) (forward direction): 8.5 [Yoshimoto91]

pH(opt): 9 [BRENDA14, Macdonald73], 9.4 [BRENDA14, Prabha90], 10 [BRENDA14, Tanabe98]

Sequence Features

Protein sequence of 7-alpha-hydroxysteroid dehydrogenase with features indicated

Feature Class Location Attached Group Citations Comment
Nucleotide-Phosphate-Binding-Region 18 -> 42 NAD+
[Tanaka96, UniProt15]
UniProt: NAD.
Amino-Acid-Sites-That-Bind 146  
UniProt: Substrate.
Mutagenesis-Variant 146  
[Tanabe98, UniProt11a]
S → A or H: Reduces activity by over 65%.
Active-Site 159  
UniProt: Proton acceptor.
Mutagenesis-Variant 159  
[Tanabe98, UniProt11a]
[Tanabe98, UniProt11a]
Y → F: Loss of activity.
Y → H: Reduces activity by 87%.
Amino-Acid-Sites-That-Bind 163  
[Tanaka96, UniProt15]
UniProt: NAD.
Mutagenesis-Variant 163  
[Tanabe98, UniProt11a]
[Tanabe98, UniProt11a]
K → R: Reduces activity by 35%.
K → I: Reduces activity by 95%.

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b1619 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10425; confirmed by SwissProt match.


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

BRENDA14: BRENDA team (2014). "Imported from BRENDA version existing on Aug 2014."

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

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

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Ishihama08: Ishihama Y, Schmidt T, Rappsilber J, Mann M, Hartl FU, Kerner MJ, Frishman D (2008). "Protein abundance profiling of the Escherichia coli cytosol." BMC Genomics 9;102. PMID: 18304323

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

Lasserre06: Lasserre JP, Beyne E, Pyndiah S, Lapaillerie D, Claverol S, Bonneu M (2006). "A complexomic study of Escherichia coli using two-dimensional blue native/SDS polyacrylamide gel electrophoresis." Electrophoresis 27(16);3306-21. PMID: 16858726

Lelong07: Lelong C, Aguiluz K, Luche S, Kuhn L, Garin J, Rabilloud T, Geiselmann J (2007). "The Crl-RpoS regulon of Escherichia coli." Mol Cell Proteomics 6(4);648-59. PMID: 17224607

LopezCampistrou05: Lopez-Campistrous A, Semchuk P, Burke L, Palmer-Stone T, Brokx SJ, Broderick G, Bottorff D, Bolch S, Weiner JH, Ellison MJ (2005). "Localization, annotation, and comparison of the Escherichia coli K-12 proteome under two states of growth." Mol Cell Proteomics 4(8);1205-9. PMID: 15911532

Macdonald73: Macdonald IA, Williams CN, Mahony DE (1973). "7Alpha-hydroxysteroid dehydrogenase from Escherichia coli B: preliminary studies." Biochim Biophys Acta 309(2);243-53. PMID: 4581498

Prabha90: Prabha V, Gupta M, Seiffge D, Gupta KG (1990). "Purification of 7 alpha-hydroxysteroid dehydrogenase from Escherichia coli strain 080." Can J Microbiol 36(2);131-5. PMID: 2186848

Tanabe98: Tanabe T, Tanaka N, Uchikawa K, Kabashima T, Ito K, Nonaka T, Mitsui Y, Tsuru M, Yoshimoto T (1998). "Roles of the Ser146, Tyr159, and Lys163 residues in the catalytic action of 7alpha-hydroxysteroid dehydrogenase from Escherichia coli." J Biochem (Tokyo) 124(3);634-41. PMID: 9722677

Tanaka96: Tanaka N, Nonaka T, Tanabe T, Yoshimoto T, Tsuru D, Mitsui Y (1996). "Crystal structures of the binary and ternary complexes of 7 alpha-hydroxysteroid dehydrogenase from Escherichia coli." Biochemistry 35(24);7715-30. PMID: 8672472

Tanaka96a: Tanaka N, Nonaka T, Yoshimoto T, Tsuru D, Mitsui Y (1996). "Crystallization and preliminary X-ray crystallographic studies of 7alpha-hydroxysteroid dehydrogenase from Escherichia coli." Acta Crystallogr D Biol Crystallogr 52(Pt 1);215-7. PMID: 15299750

UniProt11a: UniProt Consortium (2011). "UniProt version 2011-06 released on 2011-06-30 00:00:00." Database.

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

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

Weber05: Weber H, Polen T, Heuveling J, Wendisch VF, Hengge R (2005). "Genome-wide analysis of the general stress response network in Escherichia coli: sigmaS-dependent genes, promoters, and sigma factor selectivity." J Bacteriol 187(5);1591-603. PMID: 15716429

Weber06: Weber A, Kogl SA, Jung K (2006). "Time-dependent proteome alterations under osmotic stress during aerobic and anaerobic growth in Escherichia coli." J Bacteriol 188(20);7165-75. PMID: 17015655

Yoshimoto91: Yoshimoto T, Higashi H, Kanatani A, Lin XS, Nagai H, Oyama H, Kurazono K, Tsuru D (1991). "Cloning and sequencing of the 7 alpha-hydroxysteroid dehydrogenase gene from Escherichia coli HB101 and characterization of the expressed enzyme." J Bacteriol 1991;173(7);2173-9. PMID: 2007545

Yoshimoto93: Yoshimoto T, Nagai H, Ito K, Tsuru D (1993). "Location of the 7 alpha-hydroxysteroid dehydrogenase gene (hdhA) on the physical map of the Escherichia coli chromosome." J Bacteriol 175(17);5730. PMID: 8366061

Other References Related to Gene Regulation

MendozaVargas09: Mendoza-Vargas A, Olvera L, Olvera M, Grande R, Vega-Alvarado L, Taboada B, Jimenez-Jacinto V, Salgado H, Juarez K, Contreras-Moreira B, Huerta AM, Collado-Vides J, Morett E (2009). "Genome-wide identification of transcription start sites, promoters and transcription factor binding sites in E. coli." PLoS One 4(10);e7526. PMID: 19838305

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 19.0 on Sun Aug 30, 2015, biocyc14.