Escherichia coli K-12 substr. MG1655 Protein: molecular chaperone, HSP90 family

Gene: htpG Accession Numbers: EG10461 (EcoCyc), b0473, ECK0467

Synonyms: C62.5, Hsp90

Regulation Summary Diagram: ?

Regulation summary diagram for htpG

Subunit composition of molecular chaperone, HSP90 family = [HtpG]2
         HtpG monomer = HtpG

The HtpG protein is the E. coli homolog of the ubiquitous HSP90 family of proteins [Bardwell87]. The purified HtpG protein has ATPase activity with a kcat value of 3 min-1 and a KM for ATP of 500 µM; the enzyme autophosphorylates at serine and threonine residues [Nadeau93]. ATP hydrolysis is required for the function of HtpG [Panaretou98]. HtpG can bind the heat shock alternative sigma factor σ32 as well as cyclophilin [Nadeau93] and was shown to participate in folding of newly synthesized proteins under mild heat shock conditions [Thomas00].

The domain structure of the HtpG protein has been investigated. The protein is a dimer in solution [Spence89], but oligomerizes at higher temperatures [Nemoto01]. Both substrate binding and self-oligomerizing activities were found to localize to the N-terminal domain [Nemoto01]. Later studies suggested that the C-terminal region represents the substrate binding and dimerization domains [Nemoto01a, Yamada03a].

The crystal structure of the carboxy-terminal dimerization domain of HtpG has been solved at 2.6 Å resolution; dimerization is dependent on the formation of a four-helix bundle [Harris04]. The conformational dynamics of HtpG during its ATPase cycle have been studied [Shiau06, Southworth08, Huai05, Graf09].

Expression of htpG is induced by heat shock [Heitzer90, Heitzer92] and acid shock [Heyde90], is repressed by nitrogen starvation [Kabir04], and is dependent on the growth environment [Mason99]. htpG belongs to the σ32 regulon [Zhao05].

HtpG: "high temperature protein G" [Neidhardt84]

Reviews: [Lund01, Richter06]

Locations: inner membrane, cytosol

Map Position: [494,344 -> 496,218] (10.65 centisomes, 38°)
Length: 1875 bp / 624 aa

Molecular Weight of Polypeptide: 71.422 kD (from nucleotide sequence), 65.5 kD (experimental) [Spence89 ]

Molecular Weight of Multimer: 144.6 kD (experimental) [Spence89]

Unification Links: ASAP:ABE-0001642 , CGSC:17680 , DIP:DIP-29797N , EchoBASE:EB0456 , EcoGene:EG10461 , EcoliWiki:b0473 , Mint:MINT-1227806 , ModBase:P0A6Z3 , OU-Microarray:b0473 , PortEco:htpG , PR:PRO_000022937 , Pride:P0A6Z3 , Protein Model Portal:P0A6Z3 , RefSeq:NP_415006 , RegulonDB:EG10461 , SMR:P0A6Z3 , String:511145.b0473 , UniProt:P0A6Z3

Relationship Links: InterPro:IN-FAMILY:IPR001404 , InterPro:IN-FAMILY:IPR003594 , InterPro:IN-FAMILY:IPR019805 , InterPro:IN-FAMILY:IPR020568 , InterPro:IN-FAMILY:IPR020575 , Panther:IN-FAMILY:PTHR11528 , PDB:Structure:1SF8 , PDB:Structure:1Y4S , PDB:Structure:1Y4U , PDB:Structure:2GQ0 , PDB:Structure:2IOP , PDB:Structure:2IOQ , PDB:Structure:2IOR , Pfam:IN-FAMILY:PF00183 , Pfam:IN-FAMILY:PF02518 , Prints:IN-FAMILY:PR00775 , Prosite:IN-FAMILY:PS00298 , Smart:IN-FAMILY:SM00387

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for htpG

GO Terms:

Biological Process: GO:0006457 - protein folding Inferred from experiment Inferred by computational analysis [GOA06, GOA01a, Thomas00]
GO:0006974 - cellular response to DNA damage stimulus Inferred from experiment [Khil02]
GO:0009408 - response to heat Inferred from experiment [Chuang93]
GO:0006950 - response to stress Inferred by computational analysis [GOA01a]
Molecular Function: GO:0005515 - protein binding Inferred from experiment [Rajagopala14, Arifuzzaman06, Butland05]
GO:0016887 - ATPase activity Inferred from experiment [MotojimaMiyazak10]
GO:0042623 - ATPase activity, coupled Inferred from experiment [Panaretou98]
GO:0042802 - identical protein binding Inferred from experiment [Rajagopala14, Lasserre06]
GO:0000166 - nucleotide binding Inferred by computational analysis [UniProtGOA11a]
GO:0005524 - ATP binding Inferred by computational analysis [UniProtGOA11a, GOA06, GOA01a]
GO:0051082 - unfolded protein binding Inferred by computational analysis [GOA06, GOA01a]
Cellular Component: GO:0005829 - cytosol Inferred from experiment Inferred by computational analysis [DiazMejia09, Ishihama08, LopezCampistrou05, Lasserre06]
GO:0005737 - cytoplasm Inferred by computational analysis [UniProtGOA11, UniProtGOA11a, GOA06]
GO:0005886 - plasma membrane Inferred by computational analysis [UniProtGOA11, UniProtGOA11a]
GO:0016020 - membrane Inferred by computational analysis [UniProtGOA11a]

MultiFun Terms: information transfer protein related chaperoning, repair (refolding)

Essentiality data for htpG 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 ? 05-Jan-2007 by Keseler I , SRI International

Sequence Features

Protein sequence of HtpG monomer with features indicated

Feature Class Location Citations Comment
Protein-Segment 1 -> 336
UniProt: A; substrate-binding; Sequence Annotation Type: region of interest;
Amino-Acid-Sites-That-Bind 38
[Huai05, UniProt15]
UniProt: ATP.
Amino-Acid-Sites-That-Bind 80
[Huai05, UniProt15]
UniProt: ATP.
Amino-Acid-Sites-That-Bind 127
[Huai05, UniProt15]
UniProt: ATP; via amide nitrogen.
Amino-Acid-Sites-That-Bind 174
[Huai05, UniProt15]
UniProt: ATP.
Amino-Acid-Sites-That-Bind 255
[Huai05, UniProt15]
UniProt: ATP.
Protein-Segment 337 -> 552
UniProt: B; Sequence Annotation Type: region of interest;
Acetylation-Modification 362
Protein-Segment 553 -> 624
UniProt: C; Sequence Annotation Type: region of interest;
Protein-Segment 585 -> 624
UniProt: Mediates dimerization; Sequence Annotation Type: region of interest.

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Units:

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram


10/20/97 Gene b0473 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10461; confirmed by SwissProt match.


Arifuzzaman06: Arifuzzaman M, Maeda M, Itoh A, Nishikata K, Takita C, Saito R, Ara T, Nakahigashi K, Huang HC, Hirai A, Tsuzuki K, Nakamura S, Altaf-Ul-Amin M, Oshima T, Baba T, Yamamoto N, Kawamura T, Ioka-Nakamichi T, Kitagawa M, Tomita M, Kanaya S, Wada C, Mori H (2006). "Large-scale identification of protein-protein interaction of Escherichia coli K-12." Genome Res 16(5);686-91. PMID: 16606699

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

Bardwell87: Bardwell JC, Craig EA (1987). "Eukaryotic Mr 83,000 heat shock protein has a homologue in Escherichia coli." Proc Natl Acad Sci U S A 1987;84(15);5177-81. PMID: 3299380

Butland05: Butland G, Peregrin-Alvarez JM, Li J, Yang W, Yang X, Canadien V, Starostine A, Richards D, Beattie B, Krogan N, Davey M, Parkinson J, Greenblatt J, Emili A (2005). "Interaction network containing conserved and essential protein complexes in Escherichia coli." Nature 433(7025);531-7. PMID: 15690043

Chuang93: Chuang SE, Blattner FR (1993). "Characterization of twenty-six new heat shock genes of Escherichia coli." J Bacteriol 175(16);5242-52. PMID: 8349564

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

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

GOA06: GOA, SIB (2006). "Electronic Gene Ontology annotations created by transferring manual GO annotations between orthologous microbial proteins."

Graf09: Graf C, Stankiewicz M, Kramer G, Mayer MP (2009). "Spatially and kinetically resolved changes in the conformational dynamics of the Hsp90 chaperone machine." EMBO J 28(5);602-13. PMID: 19165152

Harris04: Harris SF, Shiau AK, Agard DA (2004). "The crystal structure of the carboxy-terminal dimerization domain of htpG, the Escherichia coli Hsp90, reveals a potential substrate binding site." Structure (Camb) 12(6);1087-97. PMID: 15274928

Heitzer90: Heitzer A, Mason CA, Snozzi M, Hamer G (1990). "Some effects of growth conditions on steady state and heat shock induced htpG gene expression in continuous cultures of Escherichia coli." Arch Microbiol 155(1);7-12. PMID: 2078102

Heitzer92: Heitzer A, Mason CA, Hamer G (1992). "Heat shock gene expression in continuous cultures of Escherichia coli." J Biotechnol 22(1-2);153-69. PMID: 1367813

Heyde90: Heyde M, Portalier R (1990). "Acid shock proteins of Escherichia coli." FEMS Microbiol Lett 57(1-2);19-26. PMID: 2199304

Huai05: Huai Q, Wang H, Liu Y, Kim HY, Toft D, Ke H (2005). "Structures of the N-terminal and middle domains of E. coli Hsp90 and conformation changes upon ADP binding." Structure 13(4);579-90. PMID: 15837196

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

Kabir04: Kabir MS, Sagara T, Oshima T, Kawagoe Y, Mori H, Tsunedomi R, Yamada M (2004). "Effects of mutations in the rpoS gene on cell viability and global gene expression under nitrogen starvation in Escherichia coli." Microbiology 150(Pt 8);2543-53. PMID: 15289551

Khil02: Khil PP, Camerini-Otero RD (2002). "Over 1000 genes are involved in the DNA damage response of Escherichia coli." Mol Microbiol 44(1);89-105. PMID: 11967071

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

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

Lund01: Lund PA (2001). "Microbial molecular chaperones." Adv Microb Physiol 44;93-140. PMID: 11407116

Mason99: Mason CA, Dunner J, Indra P, Colangelo T (1999). "Heat-induced expression and chemically induced expression of the Escherichia coli stress protein HtpG are affected by the growth environment." Appl Environ Microbiol 65(8);3433-40. PMID: 10427031

MotojimaMiyazak10: Motojima-Miyazaki Y, Yoshida M, Motojima F (2010). "Ribosomal protein L2 associates with E. coli HtpG and activates its ATPase activity." Biochem Biophys Res Commun 400(2);241-5. PMID: 20727857

Nadeau93: Nadeau K, Das A, Walsh CT (1993). "Hsp90 chaperonins possess ATPase activity and bind heat shock transcription factors and peptidyl prolyl isomerases." J Biol Chem 268(2);1479-87. PMID: 8419347

Neidhardt84: Neidhardt FC, VanBogelen RA, Vaughn V (1984). "The genetics and regulation of heat-shock proteins." Annu Rev Genet 18;295-329. PMID: 6442118

Nemoto01: Nemoto TK, Ono T, Tanaka K (2001). "Substrate-binding characteristics of proteins in the 90 kDa heat shock protein family." Biochem J 354(Pt 3);663-70. PMID: 11237871

Nemoto01a: Nemoto TK, Ono T, Kobayakawa T, Tanaka E, Baba TT, Tanaka K, Takagi T, Gotoh T (2001). "Domain-domain interactions of HtpG, an Escherichia coli homologue of eukaryotic HSP90 molecular chaperone." Eur J Biochem 268(20);5258-69. PMID: 11606187

Panaretou98: Panaretou B, Prodromou C, Roe SM, O'Brien R, Ladbury JE, Piper PW, Pearl LH (1998). "ATP binding and hydrolysis are essential to the function of the Hsp90 molecular chaperone in vivo." EMBO J 17(16);4829-36. PMID: 9707442

Rajagopala14: Rajagopala SV, Sikorski P, Kumar A, Mosca R, Vlasblom J, Arnold R, Franca-Koh J, Pakala SB, Phanse S, Ceol A, Hauser R, Siszler G, Wuchty S, Emili A, Babu M, Aloy P, Pieper R, Uetz P (2014). "The binary protein-protein interaction landscape of Escherichia coli." Nat Biotechnol 32(3);285-90. PMID: 24561554

Richter06: Richter K, Buchner J (2006). "hsp90: twist and fold." Cell 127(2);251-3. PMID: 17055424

Shiau06: Shiau AK, Harris SF, Southworth DR, Agard DA (2006). "Structural Analysis of E. coli hsp90 reveals dramatic nucleotide-dependent conformational rearrangements." Cell 127(2);329-40. PMID: 17055434

Southworth08: Southworth DR, Agard DA (2008). "Species-dependent ensembles of conserved conformational states define the Hsp90 chaperone ATPase cycle." Mol Cell 32(5);631-40. PMID: 19061638

Spence89: Spence J, Georgopoulos C (1989). "Purification and properties of the Escherichia coli heat shock protein, HtpG." J Biol Chem 264(8);4398-403. PMID: 2647735

Thomas00: Thomas JG, Baneyx F (2000). "ClpB and HtpG facilitate de novo protein folding in stressed Escherichia coli cells." Mol Microbiol 36(6);1360-70. PMID: 10931286

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

UniProt11a: UniProt Consortium (2011). "UniProt version 2011-11 released on 2011-11-22 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 the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

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

Yamada03a: Yamada S, Ono T, Mizuno A, Nemoto TK (2003). "A hydrophobic segment within the C-terminal domain is essential for both client-binding and dimer formation of the HSP90-family molecular chaperone." Eur J Biochem 270(1);146-54. PMID: 12492485

Yu08: Yu BJ, Kim JA, Moon JH, Ryu SE, Pan JG (2008). "The diversity of lysine-acetylated proteins in Escherichia coli." J Microbiol Biotechnol 18(9);1529-36. PMID: 18852508

Zhao05: Zhao K, Liu M, Burgess RR (2005). "The global transcriptional response of Escherichia coli to induced sigma 32 protein involves sigma 32 regulon activation followed by inactivation and degradation of sigma 32 in vivo." J Biol Chem 280(18);17758-68. PMID: 15757896

Other References Related to Gene Regulation

Barrios99: Barrios H, Valderrama B, Morett E (1999). "Compilation and analysis of sigma(54)-dependent promoter sequences." Nucleic Acids Res 27(22);4305-13. PMID: 10536136

Cowing85: Cowing DW, Bardwell JC, Craig EA, Woolford C, Hendrix RW, Gross CA (1985). "Consensus sequence for Escherichia coli heat shock gene promoters." Proc Natl Acad Sci U S A 82(9);2679-83. PMID: 3887408

Ishida09: Ishida Y, Kori A, Ishihama A (2009). "Participation of regulator AscG of the beta-glucoside utilization operon in regulation of the propionate catabolism operon." J Bacteriol 191(19);6136-44. PMID: 19633077

MedinaRivera11: Medina-Rivera A, Abreu-Goodger C, Thomas-Chollier M, Salgado H, Collado-Vides J, van Helden J (2011). "Theoretical and empirical quality assessment of transcription factor-binding motifs." Nucleic Acids Res 39(3);808-24. PMID: 20923783

Nonaka06: Nonaka G, Blankschien M, Herman C, Gross CA, Rhodius VA (2006). "Regulon and promoter analysis of the E. coli heat-shock factor, sigma32, reveals a multifaceted cellular response to heat stress." Genes Dev 20(13);1776-89. PMID: 16818608

Wade06: Wade JT, Roa DC, Grainger DC, Hurd D, Busby SJ, Struhl K, Nudler E (2006). "Extensive functional overlap between sigma factors in Escherichia coli." Nat Struct Mol Biol 13(9);806-14. PMID: 16892065

Zhao10a: Zhao K, Liu M, Burgess RR (2010). "Promoter and regulon analysis of nitrogen assimilation factor, sigma54, reveal alternative strategy for E. coli MG1655 flagellar biosynthesis." Nucleic Acids Res 38(4);1273-83. PMID: 19969540

Zhou88: Zhou YN, Kusukawa N, Erickson JW, Gross CA, Yura T (1988). "Isolation and characterization of Escherichia coli mutants that lack the heat shock sigma factor sigma 32." J Bacteriol 170(8);3640-9. PMID: 2900239

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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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