Gene Symbol: btuB
Description: vitamin B12/cobalamin outer membrane transporter
Alias: ECK3958, JW3938, bfe, cer, dcrC
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Old I, Phillips S, Stockley P, Saint Girons I. Regulation of methionine biosynthesis in the Enterobacteriaceae. Prog Biophys Mol Biol. 1991;56:145-85 pubmed
  2. Heller K, Kadner R. Nucleotide sequence of the gene for the vitamin B12 receptor protein in the outer membrane of Escherichia coli. J Bacteriol. 1985;161:904-8 pubmed
    The nucleotide sequence of a 2220-base-pair fragment containing the btuB gene of Escherichia coli was determined...
  3. Roth J, Lawrence J, Bobik T. Cobalamin (coenzyme B12): synthesis and biological significance. Annu Rev Microbiol. 1996;50:137-81 pubmed
    ..but not E. coli, have acquired by horizontal transfer the ability to synthesize B12 and degrade propanediol. The acquired ability to degrade propanediol provides the selective force that maintains B12 synthesis in this group. ..
  4. Altman S, Wesolowski D, Guerrier Takada C, Li Y. RNase P cleaves transient structures in some riboswitches. Proc Natl Acad Sci U S A. 2005;102:11284-9 pubmed
    ..This 5' UTR controls splicing of the arginase mRNA in A. nidulans. Four other riboswitches in E. coli were not cleaved by RNase P under the conditions tested. ..
  5. Shultis D, Purdy M, Banchs C, Wiener M. Crystallization and preliminary X-ray crystallographic analysis of the Escherichia coli outer membrane cobalamin transporter BtuB in complex with the carboxy-terminal domain of TonB. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2006;62:638-41 pubmed
    ..The Escherichia coli outer membrane cobalamin transporter BtuB and a carboxy-terminal domain of the TonB protein, residues 147-239 of the wild-type protein, were expressed and ..
  6. Nou X, Kadner R. Coupled changes in translation and transcription during cobalamin-dependent regulation of btuB expression in Escherichia coli. J Bacteriol. 1998;180:6719-28 pubmed
    The level of the vitamin B12 transport protein BtuB in the outer membrane of Escherichia coli is strongly reduced by growth in the presence of cobalamins...
  7. Nahvi A, Barrick J, Breaker R. Coenzyme B12 riboswitches are widespread genetic control elements in prokaryotes. Nucleic Acids Res. 2004;32:143-50 pubmed
    ..Previously, we provided evidence that the btuB mRNAs of Escherichia coli and Salmonella typhimurium each carry a coenzyme B12-dependent riboswitch that causes ..
  8. Nou X, Kadner R. Adenosylcobalamin inhibits ribosome binding to btuB RNA. Proc Natl Acad Sci U S A. 2000;97:7190-5 pubmed
    Expression of the btuB gene encoding the outer membrane cobalamin transporter in Escherichia coli is strongly reduced on growth with cobalamins...
  9. Kurisu G, Zakharov S, Zhalnina M, Bano S, Eroukova V, Rokitskaya T, et al. The structure of BtuB with bound colicin E3 R-domain implies a translocon. Nat Struct Biol. 2003;10:948-54 pubmed
    Cellular import of colicin E3 is initiated by the Escherichia coli outer membrane cobalamin transporter, BtuB. The 135-residue 100-A coiled-coil receptor-binding domain (R135) of colicin E3 forms a 1:1 complex with BtuB whose structure at ..

More Information


  1. Mohanty A, Bishop C, Bishop T, Wimley W, Wiener M. Enzymatic E-colicins bind to their target receptor BtuB by presentation of a small binding epitope on a coiled-coil scaffold. J Biol Chem. 2003;278:40953-8 pubmed
    ..Bacterial E-colicins target Escherichia coli by binding to the outer membrane cobalamin transporter BtuB. Colicins are tripartite molecules possessing receptor-binding, translocation, and toxin domains connected by long ..
  2. Chimento D, Mohanty A, Kadner R, Wiener M. Substrate-induced transmembrane signaling in the cobalamin transporter BtuB. Nat Struct Biol. 2003;10:394-401 pubmed
    ..We have solved crystal structures of BtuB, the outer membrane cobalamin transporter from Escherichia coli, in the absence and presence of cyanocobalamin (..
  3. Nahvi A, Sudarsan N, Ebert M, Zou X, Brown K, Breaker R. Genetic control by a metabolite binding mRNA. Chem Biol. 2002;9:1043 pubmed
    ..We report that the 5'-untranslated sequence of the Escherichia coli btuB mRNA assumes a more proactive role in metabolic monitoring and genetic control...
  4. Pan Y, Liao C, Kuo C, Duan K, Liang P, Yuan H, et al. The critical roles of polyamines in regulating ColE7 production and restricting ColE7 uptake of the colicin-producing Escherichia coli. J Biol Chem. 2006;281:13083-91 pubmed
    ..Our experimental results further indicated that exogenous polyamines suppress the expression of TolA, BtuB, OmpF, and OmpC proteins that are responsible for ColE7 uptake...
  5. Lukasik S, Ho K, Cafiso D. Molecular basis for substrate-dependent transmembrane signaling in an outer-membrane transporter. J Mol Biol. 2007;370:807-11 pubmed
    ..In the Escherichia coli vitamin B(12) transporter, BtuB, substrate binding to the extracellular surface of the protein triggers the unfolding of an energy coupling motif ..
  6. Freed D, Khan A, Horanyi P, Cafiso D. Molecular origin of electron paramagnetic resonance line shapes on ?-barrel membrane proteins: the local solvation environment modulates spin-label configuration. Biochemistry. 2011;50:8792-803 pubmed publisher
    ..the origins of EPR line shapes from spin-labels at the protein-lipid interface on the ?-barrel membrane protein BtuB. Two atomic-resolution structures were obtained for the methanethiosulfonate spin-label derivatized to cysteines on ..
  7. McKee R, Glass R. Deletion analysis of essential genes of Escherichia coli: investigation of the btuB-rpoBC interval. J Gen Microbiol. 1982;128:2199-202 pubmed
    ..We report the application of this technique to the study of the btuB-rpoBC interval, a cluster of genes encoding components of the transcription-translation apparatus.
  8. Masi M, Vuong P, Humbard M, Malone K, Misra R. Initial steps of colicin E1 import across the outer membrane of Escherichia coli. J Bacteriol. 2007;189:2667-76 pubmed
    ..ColE1 initially binds to the vitamin B(12) receptor BtuB and then translocates through the TolC channel-tunnel, presumably in a mostly unfolded state...
  9. Fanucci G, Coggshall K, Cadieux N, Kim M, Kadner R, Cafiso D. Substrate-induced conformational changes of the periplasmic N-terminus of an outer-membrane transporter by site-directed spin labeling. Biochemistry. 2003;42:1391-400 pubmed
    The structure and dynamics of the N-terminal and core regions of BtuB, an outer membrane vitamin B(12) transporter from Escherichia coli, were investigated by site-directed spin labeling...
  10. Etz H, Minh D, Schellack C, Nagy E, Meinke A. Bacterial phage receptors, versatile tools for display of polypeptides on the cell surface. J Bacteriol. 2001;183:6924-35 pubmed
    ..The vitamin B(12) and phage BF23 receptor BtuB could display peptide inserts of at least 86 amino acids containing the T7 tag...
  11. Koster W, Gudmundsdottir A, Lundrigan M, Seiffert A, Kadner R. Deletions or duplications in the BtuB protein affect its level in the outer membrane of Escherichia coli. J Bacteriol. 1991;173:5639-47 pubmed
    The Escherichia coli btuB product is an outer membrane protein that mediates the TonB-coupled active transport of cobalamins and the uptake of the E colicins and bacteriophage BF23...
  12. Zakharov S, Sharma O, Zhalnina M, Cramer W. Primary events in the colicin translocon: FRET analysis of colicin unfolding initiated by binding to BtuB and OmpF. Biochemistry. 2008;47:12802-9 pubmed publisher
    ..colicin E3 is initiated by high affinity binding of the colicin receptor-binding (R) domain to the vitamin B(12) (BtuB) receptor in the Escherichia coli outer membrane...
  13. Cadieux N, Kadner R. Site-directed disulfide bonding reveals an interaction site between energy-coupling protein TonB and BtuB, the outer membrane cobalamin transporter. Proc Natl Acad Sci U S A. 1999;96:10673-8 pubmed
    ..that of iron-siderophore complexes, is an active transport process requiring a specific outer membrane transporter BtuB, the proton motive force, and the trans-periplasmic energy coupling protein TonB...
  14. Lei G, Syu W, Liang P, Chak K, Hu W, Hu S. Repression of btuB gene transcription in Escherichia coli by the GadX protein. BMC Microbiol. 2011;11:33 pubmed publisher
    b>BtuB (B twelve uptake) is an outer membrane protein of Escherichia coli. It serves as a receptor for cobalamines uptake or bactericidal toxin entry. A decrease in the production of the BtuB protein would cause E...
  15. Aufrère R, Tempete M, Bohin J. [A case of overlapping reading frames in Escherichia coli]. C R Acad Sci III. 1986;303:49-54 pubmed
    The two promoters and the first 65 nucleotides of a gene related to the rrnB operon are localized in the coding sequence of the btuB gene.
  16. Pugsley A. Escherichia coli K12 strains for use in the identification and characterization of colicins. J Gen Microbiol. 1985;131:369-76 pubmed
    ..The strains can be used in typing schemes based on the identification of colicins, in the detection of new types of colicins/microcins, and in the further characterization of previously identified colicins/microcins and their plasmids. ..
  17. Hufton S, Ward R, Bunce N, Armstrong J, Fletcher A, Glass R. Structure-function analysis of the vitamin B12 receptor of Escherichia coli by means of informational suppression. Mol Microbiol. 1995;15:381-93 pubmed
    ..We have studied 22 different mutants, 14 in detail, distributed throughout the length of the btuB gene...
  18. Chimento D, Kadner R, Wiener M. The Escherichia coli outer membrane cobalamin transporter BtuB: structural analysis of calcium and substrate binding, and identification of orthologous transporters by sequence/structure conservation. J Mol Biol. 2003;332:999-1014 pubmed
    ..In Escherichiacoli, the TonB-dependent outer membrane transporter BtuB carries out active transport of cobalamin (Cbl) substrates across its outer membrane...
  19. Fanucci G, Cadieux N, Kadner R, Cafiso D. Competing ligands stabilize alternate conformations of the energy coupling motif of a TonB-dependent outer membrane transporter. Proc Natl Acad Sci U S A. 2003;100:11382-7 pubmed
    b>BtuB is a TonB-dependent outer-membrane transporter for vitamin B12 (or cyanocobalamin, CN-Cbl) in Escherichia coli...
  20. Gudmundsdottir A, Bell P, Lundrigan M, Bradbeer C, Kadner R. Point mutations in a conserved region (TonB box) of Escherichia coli outer membrane protein BtuB affect vitamin B12 transport. J Bacteriol. 1989;171:6526-33 pubmed
    ..The btuB product is the outer membrane receptor for cobalamins, bacteriophage BF23, and the E colicins...
  21. Gustafsson C, Lindström P, Hagervall T, Esberg K, Björk G. The trmA promoter has regulatory features and sequence elements in common with the rRNA P1 promoter family of Escherichia coli. J Bacteriol. 1991;173:1757-64 pubmed
    ..The trmA and the btuB (encoding the vitamin B12 outer membrane receptor protein) promoters are divergent promoters separated by 102 bp ..
  22. Fletcher A, Pugsley A, Glass R. Investigation of the regulation of the Escherichia coli btuB gene using operon fusions. J Gen Microbiol. 1986;132:2643-6 pubmed
    Operon fusions were isolated between Mu dX (lac CmR ApR) and btuB, the gene encoding the multivalent vitamin B12 outer membrane receptor. Using these fusions, vitamin B12-mediated repression of btuB in Escherichia coli was demonstrated...
  23. Hunter M, Glass R. Analysis of btuB receptor function by use of nonsense suppression. J Bacteriol. 1982;151:1591-4 pubmed
    Informational suppression of btuB nonsense mutants allows the study of the effect of known, single amino acid substitutions on receptor function. We found that ligand uptake is largely unaffected by such amino acid changes...
  24. Luan B, Carr R, Caffrey M, Aksimentiev A. The effect of calcium on the conformation of cobalamin transporter BtuB. Proteins. 2010;78:1153-62 pubmed publisher
    b>BtuB is a beta-barrel membrane protein that facilitates transport of cobalamin (vitamin B12) from the extracellular medium across the outer membrane of Escherichia coli...
  25. Sauter A, Braun V. Defined inactive FecA derivatives mutated in functional domains of the outer membrane transport and signaling protein of Escherichia coli K-12. J Bacteriol. 2004;186:5303-10 pubmed
    ..Comparison of the properties of the FecA, FhuA, FepA, and BtuB transporters indicates that although they have very similar crystal structures, the details of their functional ..
  26. Kadner R, Heller K. Mutual inhibition of cobalamin and siderophore uptake systems suggests their competition for TonB function. J Bacteriol. 1995;177:4829-35 pubmed
    ..which the amount of the outer membrane ferrichrome transporter FhuA far exceeds that of the cobalamin transporter BtuB, CN-Cbl does inhibit ferrichrome uptake when BtuB is overexpressed from a multicopy plasmid...
  27. Kim M, Xu Q, Murray D, Cafiso D. Solutes alter the conformation of the ligand binding loops in outer membrane transporters. Biochemistry. 2008;47:670-9 pubmed
    ..resonance (EPR) spectroscopy were used to examine the effect of stabilizing solutes on the extracellular loops in BtuB, the vitamin B12 transporter, and FecA, the ferric citrate transporter...
  28. Bonsor D, Meenan N, Kleanthous C. Colicins exploit native disorder to gain cell entry: a hitchhiker's guide to translocation. Biochem Soc Trans. 2008;36:1409-13 pubmed publisher
    ..previously shown that uptake of ColE9 (colicin E9) is dependent on engagement of the OM (outer membrane) receptors BtuB and OmpF as well as recruitment of the periplasmic protein TolB, forming a large supramolecular complex...
  29. Zheng Y, Roberts R, Kasif S. Segmentally variable genes: a new perspective on adaptation. PLoS Biol. 2004;2:E81 pubmed
    ..Discerning their function and identifying their binding partners may offer biologists new insights into the basic mechanisms of adaptation, context-dependent evolution, and the interaction between microbes and their environment. ..
  30. Coggshall K, Cadieux N, Piedmont C, Kadner R, Cafiso D. Transport-defective mutations alter the conformation of the energy-coupling motif of an outer membrane transporter. Biochemistry. 2001;40:13964-71 pubmed
    The bacterial outer membrane transporter for vitamin B(12), BtuB, derives its energy for transport by interacting with the trans-periplasmic membrane protein TonB...
  31. Zakharov S, Cramer W. On the mechanism and pathway of colicin import across the E. Coli outer membrane. Front Biosci. 2004;9:1311-7 pubmed
    ..3D crystal structures recently obtained of the cobalamin (vitamin B12) receptor (BtuB), and of the complex of BtuB with the 135 residue receptor binding domain (R135) of colicin E3, have provided some ..
  32. Merianos H, Cadieux N, Lin C, Kadner R, Cafiso D. Substrate-induced exposure of an energy-coupling motif of a membrane transporter. Nat Struct Biol. 2000;7:205-9 pubmed
    b>BtuB is an outer membrane protein responsible for the uptake of vitamin B12 by Escherichia coli...
  33. Aufrère R, Tempete M, Bohin J. Regulation of expression of the gene for vitamin B12 receptor cloned on a multicopy plasmid in Escherichia coli. Mol Gen Genet. 1986;205:358-65 pubmed
    The btuB gene of Escherichia coli codes for a protein (BtuB) located in the outer membrane. BtuB is the receptor for vitamin B12 (cyanocobalamin)...
  34. Lee Y, Hu H, Liang P, Chak K. An E. coli lon mutant conferring partial resistance to colicin may reveal a novel role in regulating proteins involved in the translocation of colicin. Biochem Biophys Res Commun. 2006;345:1579-85 pubmed
    ..The results of Western blotting detected a decrease in the protein expression levels of BtuB and OmpF involved in colicin translocation in the lon mutant...
  35. Santillan M, Mackey M. Dynamic behaviour of the B12 riboswitch. Phys Biol. 2005;2:29-35 pubmed
    ..This behaviour is discussed in terms of a possible evolutionary advantage for E. coli, together with the fact that regulation at the transcriptional and translational levels is almost equivalent dynamically. ..
  36. Xu Q, Ellena J, Kim M, Cafiso D. Substrate-dependent unfolding of the energy coupling motif of a membrane transport protein determined by double electron-electron resonance. Biochemistry. 2006;45:10847-54 pubmed
    b>BtuB is a TonB-dependent transport protein that binds and carries vitamin B(12) across the outer membrane of Gram negative bacteria such as Escherichia coli...
  37. Samsonov V, Samsonov V, Sineoky S. DcrA and dcrB Escherichia coli genes can control DNA injection by phages specific for BtuB and FhuA receptors. Res Microbiol. 2002;153:639-46 pubmed
    ..inner membrane and periplasm, are involved in the early development of virulent bacteriophage C1, which recognises BtuB as an outer membrane receptor...
  38. Bradbeer C, Reynolds P, Bauler G, Fernandez M. A requirement for calcium in the transport of cobalamin across the outer membrane of Escherichia coli. J Biol Chem. 1986;261:2520-3 pubmed
    ..Cbl) transport across the outer membrane of cells of Escherichia coli consists of high affinity Cbl binding to the btuB protein of the Cbl receptor, followed by the proton motive force- and tonB-dependent release of the Cbl into the ..
  39. Buxton R. Genetic analysis of Escherichia coli K12 mutants resistant to bacteriophage BF23 and the E-group colicins. Mol Gen Genet. 1971;113:154-6 pubmed
  40. Deneer H, Spiegelman G. Bacillus subtilis rRNA promoters are growth rate regulated in Escherichia coli. J Bacteriol. 1987;169:995-1002 pubmed
    ..The downstream promoter of the tandem Bacillus pair showed growth rate regulation, while the upstream promoter did not, whereas for the E. coli tandem promoters, only the upstream promoter was growth rate regulated. ..
  41. Kadner R, Liggins G. Transport of vitamin B12 in Escherichia coli: genetic studies. J Bacteriol. 1973;115:514-21 pubmed
    ..The other locus, btuB, apparently codes for the surface receptor on the outer membrane...
  42. Zakharov S, Eroukova V, Rokitskaya T, Zhalnina M, Sharma O, Loll P, et al. Colicin occlusion of OmpF and TolC channels: outer membrane translocons for colicin import. Biophys J. 2004;87:3901-11 pubmed
    ..Colicins E1 and E3 initially bind to the BtuB receptor, whose beta-barrel pore is occluded by an N-terminal globular "plug"...
  43. Bradbeer C, Kenley J, Di Masi D, Leighton M. Transport of vitamin B12 in Escherichia coli. Corrinoid specificities of the periplasmic B12-binding protein and of energy-dependent B12 transport. J Biol Chem. 1978;253:1347-52 pubmed
  44. Zakharov S, Zhalnina M, Sharma O, Cramer W. The colicin E3 outer membrane translocon: immunity protein release allows interaction of the cytotoxic domain with OmpF porin. Biochemistry. 2006;45:10199-207 pubmed
    The crystal structure previously obtained for the complex of BtuB and the receptor binding domain of colicin E3 forms a basis for further analysis of the mechanism of colicin import through the bacterial outer membrane...
  45. Lussier A, Bastet L, Chauvier A, Lafontaine D. A kissing loop is important for btuB riboswitch ligand sensing and regulatory control. J Biol Chem. 2015;290:26739-51 pubmed publisher
    ..Crystal structures show that the Escherichia coli btuB riboswitch contains a kissing loop interaction that is in close proximity to the bound ligand...
  46. Gudmundsdottir A, Bradbeer C, Kadner R. Altered binding and transport of vitamin B12 resulting from insertion mutations in the Escherichia coli btuB gene. J Biol Chem. 1988;263:14224-30 pubmed
    The BtuB protein of Escherichia coli is a multifunctional outer membrane receptor required for the binding and uptake of vitamin B12, bacteriophage BF23, and the E colicins...
  47. Fanucci G, Lee J, Cafiso D. Membrane mimetic environments alter the conformation of the outer membrane protein BtuB. J Am Chem Soc. 2003;125:13932-3 pubmed
    ..spin labeling (SDSL), we show that micelle and isotropic bicellar environments alter the N-terminal region of BtuB, the outer membrane vitamin B12 transporter found in Escherichia coli...
  48. Fuller Schaefer C, Kadner R. Multiple extracellular loops contribute to substrate binding and transport by the Escherichia coli cobalamin transporter BtuB. J Bacteriol. 2005;187:1732-9 pubmed
    ..The extracellular loops on the N-terminal half of the transmembrane beta-barrel of the cobalamin transporter BtuB participate in binding of the cofactor calcium atoms and undergo substantial conformation changes upon substrate ..
  49. Flores Jiménez R, Cafiso D. The N-terminal domain of a TonB-dependent transporter undergoes a reversible stepwise denaturation. Biochemistry. 2012;51:3642-50 pubmed publisher
    ..denaturation, we examined the site-specific unfolding of regions of the Escherichia coli vitamin B(12) transporter, BtuB. The data indicate that a portion of the N-terminal region of the protein, which occupies the lumen of the BtuB ..
  50. Lathrop J, Wei B, Touchie G, Kadner R. Sequences of the Escherichia coli BtuB protein essential for its insertion and function in the outer membrane. J Bacteriol. 1995;177:6810-9 pubmed
    The Escherichia coli btuB gene encodes the outer membrane transporter for vitamin B12, the E colicins, colicin A, and bacteriophage BF23...
  51. Cadieux N, Barekzi N, Bradbeer C. Observations on the calcium dependence and reversibility of cobalamin transport across the outer membrane of Escherichia coli. J Biol Chem. 2007;282:34921-8 pubmed
    The calcium dependence of cobalamin (Cbl) binding to the BtuB protein of Escherichia coli and the reversibility of its function in the transport of Cbl across the outer membrane have been examined...
  52. Cadieux N, Bradbeer C, Reeger Schneider E, Koster W, Mohanty A, Wiener M, et al. Identification of the periplasmic cobalamin-binding protein BtuF of Escherichia coli. J Bacteriol. 2002;184:706-17 pubmed
    ..across the outer membrane and its accumulation in the periplasm is mediated by the TonB-dependent transporter BtuB. Transport across the cytoplasmic membrane (CM) requires the BtuC and BtuD proteins, which are most related in ..
  53. Sharma O, Yamashita E, Zhalnina M, Zakharov S, Datsenko K, Wanner B, et al. Structure of the complex of the colicin E2 R-domain and its BtuB receptor. The outer membrane colicin translocon. J Biol Chem. 2007;282:23163-70 pubmed
    The crystal structure of the complex of the BtuB receptor and the 135-residue coiled-coil receptor-binding R-domain of colicin E3 (E3R135) suggested a novel mechanism for import of colicin proteins across the outer membrane...
  54. Cadieux N, Bradbeer C, Kadner R. Sequence changes in the ton box region of BtuB affect its transport activities and interaction with TonB protein. J Bacteriol. 2000;182:5954-61 pubmed
    Uptake of cobalamins by the transporter protein BtuB in the outer membrane of Escherichia coli requires the proton motive force and the transperiplasmic protein TonB...
  55. Bassford P, Bradbeer C, Kadner R, Schnaitman C. Transport of vitamin B12 in tonB mutants of Escherichia coli. J Bacteriol. 1976;128:242-7 pubmed
    ..Maltose uptake, mediated by another transport system involving an outer membrane component, was unaffected by the tonB mutation. ..
  56. Chimento D, Mohanty A, Kadner R, Wiener M. Crystallization and initial X-ray diffraction of BtuB, the integral membrane cobalamin transporter of Escherichia coli. Acta Crystallogr D Biol Crystallogr. 2003;59:509-11 pubmed
    b>BtuB, the cobalamin transporter from Escherichia coli, has been overexpressed, purified and crystallized...
  57. Cadieux N, Phan P, Cafiso D, Kadner R. Differential substrate-induced signaling through the TonB-dependent transporter BtuB. Proc Natl Acad Sci U S A. 2003;100:10688-93 pubmed
    The BtuB transporter mediates high-affinity binding and TonB-dependent active transport of vitamin B12 [cyanocobalamin (CNCbl)] across the outer membrane of Escherichia coli...
  58. Duché D, Issouf M, Lloubes R. Immunity protein protects colicin E2 from OmpT protease. J Biochem. 2009;145:95-101 pubmed publisher
    ..ColE2 interaction with the target cell outer membrane BtuB protein and Tol import machinery allows the dissociation of Im2 from its colicin at the outer membrane surface...
  59. Fanucci G, Lee J, Cafiso D. Spectroscopic evidence that osmolytes used in crystallization buffers inhibit a conformation change in a membrane protein. Biochemistry. 2003;42:13106-12 pubmed
    b>BtuB is a bacterial outer-membrane protein that transports vitamin B(12)...
  60. Likhacheva N, Samsonov V, Sineoky S. Genetic control of the resistance to phage C1 of Escherichia coli K-12. J Bacteriol. 1996;178:5309-15 pubmed
    ..Its adsorption is controlled by at least three bacterial genes: dcrA, dcrB, and btuB. Our results provide evidence that the dcrA gene located at 60 min on the E...
  61. Dougherty T, Thanassi J, Pucci M. The Escherichia coli mutant requiring D-glutamic acid is the result of mutations in two distinct genetic loci. J Bacteriol. 1993;175:111-6 pubmed
    ..To construct D-glutamate auxotrophs, it is necessary to transfer sequentially the mutated gltS locus, and then the mutated dga locus into the recipient. The sequences of the mutant forms of both dga and gltS are also presented. ..
  62. Shultis D, Purdy M, Banchs C, Wiener M. Outer membrane active transport: structure of the BtuB:TonB complex. Science. 2006;312:1396-9 pubmed
    ..We solved the structure of the cobalamin transporter BtuB in complex with the C-terminal domain of TonB...
  63. Moran M, Mazaitis A, Vogel R, Vogel H. Clustered arg genes on a BamHI segment of the Escherichia coli chromosome. Gene. 1979;8:25-34 pubmed
    BamHI cleavage of DNAs from transducing phages gamma darg13 (ppc, argECBH, bfe), gamma darg14 (ppc, argECBH) and gamma darg23 (argECBH) yields three purely gamma DNA segments (and, in one case, a fourth), as well as several Excherichia ..
  64. Housden N, Loftus S, Moore G, James R, Kleanthous C. Cell entry mechanism of enzymatic bacterial colicins: porin recruitment and the thermodynamics of receptor binding. Proc Natl Acad Sci U S A. 2005;102:13849-54 pubmed
    Binding of enzymatic E colicins to the vitamin B12 receptor, BtuB, is the first stage in a cascade of events that culminate in the translocation of the cytotoxic nuclease into the Escherichia coli cytoplasm and release of its tightly ..
  65. Choudhary P, Sigel R. Mg(2+)-induced conformational changes in the btuB riboswitch from E. coli. RNA. 2014;20:36-45 pubmed publisher
    ..The btuB riboswitch from Escherichia coli undergoes a conformational change upon binding to its ligand, coenzyme B12 (..