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Transmembrane topology of the Acr3 family arsenite transporter from Bacillus subtilis.

Aaltonen, Emil LU and Silow, Maria (2008) In Biochimica et Biophysica Acta - Biomembranes 1778(4). p.963-973
Abstract
The transmembrane topology of the Acr3 family arsenite transporter Acr3 from Bacillus subtilis was analysed experimentally using translational fusions with alkaline phosphatase and green fluorescent protein and in silico by topology modelling. Initial topology prediction resulted in two models with 9 and 10 TM helices respectively. 32 fusion constructs were made between truncated forms of acr3 and the reporter genes at 17 different sites throughout the acr3 sequence to discriminate between these models. Nine strong reporter protein signals provided information about the majority of the locations of the cytoplasmic and extracellular loops of Acr3 and showed that both the N- and the C-termini are located in the cytoplasm. Two ambiguous data... (More)
The transmembrane topology of the Acr3 family arsenite transporter Acr3 from Bacillus subtilis was analysed experimentally using translational fusions with alkaline phosphatase and green fluorescent protein and in silico by topology modelling. Initial topology prediction resulted in two models with 9 and 10 TM helices respectively. 32 fusion constructs were made between truncated forms of acr3 and the reporter genes at 17 different sites throughout the acr3 sequence to discriminate between these models. Nine strong reporter protein signals provided information about the majority of the locations of the cytoplasmic and extracellular loops of Acr3 and showed that both the N- and the C-termini are located in the cytoplasm. Two ambiguous data points indicated the possibility of an alternative 8 helix topology. This possibility was investigated using another 10 fusion variants, but no experimental support for the 8 TM topology was obtained. We therefore conclude that Acr3 has 10 transmembrane helices. Overall, the loops which connect the membrane spanning segments are short, with cytoplasmic loops being somewhat longer than the extracellular loops. The study provides the first ever experimentally derived structural information on a protein of the Acr3 family which constitutes one of the largest classes of arsenite transporters. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Translational fusion, Acr3, Transmembrane topology, GFP, Arsenite, Alkaline phosphatase
in
Biochimica et Biophysica Acta - Biomembranes
volume
1778
issue
4
pages
963 - 973
publisher
Elsevier
external identifiers
  • pmid:18088595
  • wos:000255228000017
  • scopus:40949115926
ISSN
0005-2736
DOI
10.1016/j.bbamem.2007.11.011
language
English
LU publication?
yes
id
a9abe0b7-52f8-4d93-8fae-bdc0611e6025 (old id 1035158)
date added to LUP
2008-04-28 13:49:10
date last changed
2017-07-30 03:57:09
@article{a9abe0b7-52f8-4d93-8fae-bdc0611e6025,
  abstract     = {The transmembrane topology of the Acr3 family arsenite transporter Acr3 from Bacillus subtilis was analysed experimentally using translational fusions with alkaline phosphatase and green fluorescent protein and in silico by topology modelling. Initial topology prediction resulted in two models with 9 and 10 TM helices respectively. 32 fusion constructs were made between truncated forms of acr3 and the reporter genes at 17 different sites throughout the acr3 sequence to discriminate between these models. Nine strong reporter protein signals provided information about the majority of the locations of the cytoplasmic and extracellular loops of Acr3 and showed that both the N- and the C-termini are located in the cytoplasm. Two ambiguous data points indicated the possibility of an alternative 8 helix topology. This possibility was investigated using another 10 fusion variants, but no experimental support for the 8 TM topology was obtained. We therefore conclude that Acr3 has 10 transmembrane helices. Overall, the loops which connect the membrane spanning segments are short, with cytoplasmic loops being somewhat longer than the extracellular loops. The study provides the first ever experimentally derived structural information on a protein of the Acr3 family which constitutes one of the largest classes of arsenite transporters.},
  author       = {Aaltonen, Emil and Silow, Maria},
  issn         = {0005-2736},
  keyword      = {Translational fusion,Acr3,Transmembrane topology,GFP,Arsenite,Alkaline phosphatase},
  language     = {eng},
  number       = {4},
  pages        = {963--973},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Biomembranes},
  title        = {Transmembrane topology of the Acr3 family arsenite transporter from Bacillus subtilis.},
  url          = {http://dx.doi.org/10.1016/j.bbamem.2007.11.011},
  volume       = {1778},
  year         = {2008},
}