Protein Translocation by Bacterial Toxin Channels: A Comparison of Diphtheria Toxin and Colicin Ia

Regions of both colicin Ia and diphtheria toxin N-terminal to the channel-forming domains can be translocated across planar phospholipid bilayer membranes. In this article we show that the translocation pathway of diphtheria toxin allows much larger molecules to be translocated than does the translo...

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Published inBiophysical journal Vol. 91; no. 9; pp. 3249 - 3256
Main Authors Wu, Zhengyan, Jakes, Karen S., Samelson-Jones, Ben S., Lai, Bing, Zhao, Gang, London, Erwin, Finkelstein, Alan
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 01.11.2006
Biophysical Society
Subjects
Bacterial proteins
Channels, Receptors, and Electrical Signaling
Colicins - chemistry
Diphtheria Toxin - chemistry
Gram-positive bacteria
Lipid Bilayers - chemistry
Myoglobin - chemistry
Phospholipids - chemistry
Protein Transport
Respiratory diseases
Toxins
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Summary:Regions of both colicin Ia and diphtheria toxin N-terminal to the channel-forming domains can be translocated across planar phospholipid bilayer membranes. In this article we show that the translocation pathway of diphtheria toxin allows much larger molecules to be translocated than does the translocation pathway of colicin Ia. In particular, the folded A chain of diphtheria toxin is readily translocated by that toxin but is not translocated by colicin Ia. This difference cannot be attributed to specific recognition of the A chain by diphtheria toxin’s translocation pathway because the translocation pathway also accommodates folded myoglobin.
Bibliography:Address reprint requests to Karen S. Jakes, Albert Einstein College of Medicine, Dept. of Physiology and Biophysics, 1300 Morris Park Avenue, Bronx, NY 10461. Tel.: 718-430-3169; E-mail: jakes@aecom.yu.edu.
ISSN:0006-3495
1542-0086
DOI:10.1529/biophysj.106.085753