Journal home
Advance online publication
Current issue
Archive
Press releases
Supplements
Focus
Guide to authors
Online submissionOnline submission
Permissions
For referees
Free online issue
Contact the journal
Subscribe
Advertising
work@npg
naturereprints
About this site
For librarians
 
Nature Research Resources
Nature
Nature Cell Biology
Nature Reviews Molecular Cell Biology
The EMBO Journal
Nature Reports Avian Flu
NPG Subject areas
Biotechnology
Cancer
Chemistry
Clinical Medicine
Dentistry
Development
Drug Discovery
Earth Sciences
Evolution & Ecology
Genetics
Immunology
Materials Science
Medical Research
Microbiology
Molecular Cell Biology
Neuroscience
Pharmacology
Physics
Browse all publications
Article
Nature Structural Biology  6, 56 - 63 (1999)
doi:10.1038/4931

Crystal structure of the outer membrane active transporter FepA from Escherichia coli

Susan K. Buchanan1, 3, Barbara S. Smith1, Lalitha Venkatramani2, Di Xia1, Lothar Esser1, Maya Palnitkar1, Ranjan Chakraborty2, Dick van der Helm2 & Johann Deisenhofer1

1  Howard Hughes Medical Institute, and Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75235−9050, USA.

2  Department of Chemistry and Biochemistry, The University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019−0370, USA.

3  Present address: Department of Crystallography, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.

Correspondence should be addressed to Johann Deisenhofer Johann.Deisenhofer@email.swmed.edu
Integral outer membrane receptors for iron chelates and vitamin B 12 carry out specific ligand transport against a concentration gradient. Energy for active transport is obtained from the proton−motive force of the inner membrane through physical interaction with TonB−ExbB−ExbD, an inner membrane complex. Here we report the crystal structure of an active transport, outer membrane receptor at 2.4 Å resolution. Two distinct functional domains are revealed: (i) a 22−stranded beta−barrel that spans the outer membrane and contains large extracellular loops which appear to function in ligand binding; and (ii) a globular N−terminal domain that folds into the barrel pore, inhibiting access to the periplasm and contributing two additional loops for potential ligand binding. These loops could provide a signaling pathway between the processes of ligand recognition and TonB−mediated transport. The blockage of the pore suggests that the N−terminal domain must undergo a conformational rearrangement to allow ligand transport into the periplasm.

 Top
Abstract
Previous | Next
Table of contents
Full textFull text
Download PDFDownload PDF
Send to a friendSend to a friend
Save this linkSave this link

natureevents

Figures & Tables
See also: News and Views by Postle
Export citation
natureproducts

Search buyers guide:

 
ADVERTISEMENT
 
Nature Structural & Molecular Biology
ISSN: 1545-9993
EISSN: 1545-9985
Journal home | Advance online publication | Current issue | Archive | Press releases | Supplements | For authors | Online submission | Permissions | For referees | Free online issue | About the journal | Contact the journal | Subscribe | Advertising | work@npg | naturereprints | About this site | For librarians
Nature Publishing Group, publisher of Nature, and other science journals and reference works©1999 Nature Publishing Group | Privacy policy