Functional and structural characterization of the first prokaryotic member of the L-amino acid transporter (LAT) family: a model for APC transporters

Reig, Núria; del Rio, César; Casagrande, Fabio; Ratera, Mercè; Gelpí, Josep Lluís; Torrents, David; Henderson, Peter J F; Xie, Hao; Baldwin, Stephen A; Zorzano, Antonio; Fotiadis, Dimitrios; Palacín, Manuel (2007). Functional and structural characterization of the first prokaryotic member of the L-amino acid transporter (LAT) family: a model for APC transporters. Journal of biological chemistry, 282(18), pp. 13270-81. Bethesda, Md.: American Society for Biochemistry and Molecular Biology 10.1074/jbc.M610695200

Full text not available from this repository. (Request a copy)

We have identified YkbA from Bacillus subtilis as a novel member of the L-amino acid transporter (LAT) family of amino acid transporters. The protein is approximately 30% identical in amino acid sequence to the light subunits of human heteromeric amino acid transporters. Purified His-tagged YkbA from Escherichia coli membranes reconstituted in proteoliposomes exhibited sodium-independent, obligatory exchange activity for L-serine and L-threonine and also for aromatic amino acids, albeit with less activity. Thus, we propose that YkbA be renamed SteT (Ser/Thr exchanger transporter). Kinetic analysis supports a sequential mechanism of exchange for SteT. Freeze-fracture analysis of purified, functionally active SteT in proteoliposomes, together with blue native polyacrylamide gel electrophoresis and transmission electron microscopy of detergent-solubilized purified SteT, suggest that the transporter exists in a monomeric form. Freeze-fracture analysis showed spherical particles with a diameter of 7.4 nm. Transmission electron microscopy revealed elliptical particles (diameters 6 x 7 nm) with a distinct central depression. To our knowledge, this is the first functional characterization of a prokaryotic member of the LAT family and the first structural data on an APC (amino acids, polyamines, and choline for organocations) transporter. SteT represents an excellent model to study the molecular architecture of the light subunits of heteromeric amino acid transporters and other APC transporters.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Biochemistry and Molecular Medicine

UniBE Contributor:

Fotiadis, Dimitrios José

ISSN:

0021-9258

ISBN:

17344220

Publisher:

American Society for Biochemistry and Molecular Biology

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:53

Last Modified:

04 May 2014 23:15

Publisher DOI:

10.1074/jbc.M610695200

PubMed ID:

17344220

Web of Science ID:

000246060300015

URI:

https://boris.unibe.ch/id/eprint/22702 (FactScience: 36079)

Actions (login required)

Edit item Edit item
Provide Feedback