|Gene:||tehB||Accession Numbers: EG11884 (MetaCyc), b1430, ECK1423|
Species: Escherichia coli K-12 substr. MG1655
TehB was shown to have tellurite methyltransferase activity [Choudhury11]. TehB was earlier shown to cause a SAM-dependent loss of TeO32- from an assay mixture; the reaction product was unknown, but does not consist of a volatile form of methylated tellurium [Liu00b].
The TehB protein in conjunction with TehA confers resistance to tellurite when expressed on a multicopy plasmid [Turner95]. Sequence analysis of TehB showed the presence of conserved sequence motifs occurring in S-adenosylmethionine (SAM)-dependent non-nucleic acid methyltransferases, and site-directed mutagenesis of conserved residues cause loss of tellurite resistance [Liu00b]. Cysteine residues in TehB have also been shown to be involved in tellurite resistance [DyllickBrenzing00].
Dynamic light-scattering experiments show a conformational change upon addition of SAM and TeO32-, indicating that TehB binds both SAM and tellurite. Measurement of the hydrodynamic radius indicates that the protein is a dimer in solution [Liu00b]; the dimer form appears to be stabilized upon tellurite exposure [DyllickBrenzing00]. Crystal structures of TehB in the presence of the cofactor analogs SAH (1.48 Å resolution) and sinefungin (1.9 Å resolution) have been solved [Choudhury10, Choudhury11]. The active site Arg177 residue was predicted from the structures and confirmed by site-directed mutagenesis [Choudhury11].
Tellurite resistance conferred by tehAB is limited to growth in rich medium and is dependent on the presence of a functional electron transport chain and functional quinone pool in the cell [Turner95a].
|Map Position: [1,499,586 -> 1,500,179]|
Molecular Weight of Polypeptide: 22.531 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0004772 , CGSC:32109 , DIP:DIP-10978N , EchoBASE:EB1830 , EcoGene:EG11884 , EcoliWiki:b1430 , Mint:MINT-1274665 , ModBase:P25397 , OU-Microarray:b1430 , PortEco:tehB , PR:PRO_000024047 , Protein Model Portal:P25397 , RefSeq:NP_415947 , RegulonDB:EG11884 , SMR:P25397 , String:511145.b1430 , UniProt:P25397
|Biological Process:||GO:0046690 - response to tellurium ion
[UniProtGOA11a, GOA01a, DyllickBrenzing00]
GO:0009636 - response to toxic substance [UniProtGOA11a]
GO:0032259 - methylation [UniProtGOA11a]
GO:0046677 - response to antibiotic [UniProtGOA11a]
|Molecular Function:||GO:0008757 - S-adenosylmethionine-dependent methyltransferase activity
GO:0008168 - methyltransferase activity [UniProtGOA11a]
GO:0016740 - transferase activity [UniProtGOA11a]
|Cellular Component:||GO:0005829 - cytosol
[DiazMejia09, Ishihama08, LopezCampistrou05]
GO:0005737 - cytoplasm [UniProtGOA11, UniProtGOA11a, GOA01a]
|MultiFun Terms:||cell processes → protection → drug resistance/sensitivity|
Enzymatic reaction of: tellurite methyltransferase
EC Number: 220.127.116.115
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 physiologically favored in the direction shown.
|Protein-Segment||86 -> 87|
10/20/97 Gene b1430 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11884; confirmed by SwissProt match.
Choudhury10: Choudhury HG, Beis K (2010). "Crystallization and initial X-ray diffraction analysis of the tellurite-resistance S-adenosyl-L-methionine transferase protein TehB from Escherichia coli." Acta Crystallogr Sect F Struct Biol Cryst Commun 66(Pt 11);1496-9. PMID: 21045305
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
DyllickBrenzing00: Dyllick-Brenzinger M, Liu M, Winstone TL, Taylor DE, Turner RJ (2000). "The role of cysteine residues in tellurite resistance mediated by the TehAB determinant." Biochem Biophys Res Commun 277(2);394-400. PMID: 11032735
Liu00b: Liu M, Turner RJ, Winstone TL, Saetre A, Dyllick-Brenzinger M, Jickling G, Tari LW, Weiner JH, Taylor DE (2000). "Escherichia coli TehB requires S-adenosylmethionine as a cofactor to mediate tellurite resistance." J Bacteriol 182(22);6509-13. PMID: 11053398
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
Turner95: Turner RJ, Weiner JH, Taylor DE (1995). "Neither reduced uptake nor increased efflux is encoded by tellurite resistance determinants expressed in Escherichia coli." Can J Microbiol 41(1);92-8. PMID: 7728659
Turner95a: Turner RJ, Weiner JH, Taylor DE (1995). "The tellurite-resistance determinants tehAtehB and klaAklaBtelB have different biochemical requirements." Microbiology 141 ( Pt 12);3133-40. PMID: 8574407
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