The overall goal of our research is a better understanding of biological membrane structure and function, including lipid- protein interaction, protein-protein interaction and membrane protein folding. Development of new and more reliable biochemical and biophysical methods, especially fluorescence techniques, is of special concern. We are developing new fluroescence quenching techniques which probe hydrophobicity, the depth of protein penetration into membranes and the oligomeric state of membrane proteins. It is an important aim of this project to demonstrate the power of these methods which we believe will find general use in studies of membrane structure. Specifically, our goal is to understand the behavior of diphtheria toxin. Three steps in the entry of this toxin into cells are under study. First, how and why the toxin changes from a hydrophilic to hydrophobic state. Second, the nature of the conformation of the toxin once inserted into a membrane. Third, how the poisonous A subunit of the toxin is released into the cytoplasm. These studies should increase our knowledge of insertion of proteins into membranes and translocations across membranes. Also, these studies will help in the rational design of improved immunotoxins for therapeutic application. Finally, they should shed light of the behavior of related toxin proteins and viral fusion proteins. Eventually these investigations will be extended to such proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031986-05
Application #
3280457
Study Section
Physical Biochemistry Study Section (PB)
Project Start
1983-04-01
Project End
1989-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
5
Fiscal Year
1988
Total Cost
Indirect Cost
Name
State University New York Stony Brook
Department
Type
Schools of Arts and Sciences
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794
Wang, Jie; London, Erwin (2009) The membrane topography of the diphtheria toxin T domain linked to the a chain reveals a transient transmembrane hairpin and potential translocation mechanisms. Biochemistry 48:10446-56
Lai, Bing; Zhao, Gang; London, Erwin (2008) Behavior of the deeply inserted helices in diphtheria toxin T domain: helices 5, 8, and 9 interact strongly and promote pore formation, while helices 6/7 limit pore formation. Biochemistry 47:4565-74
Fujita, Kentaro; Krishnakumar, Shyam S; Franco, David et al. (2007) Membrane topography of the hydrophobic anchor sequence of poliovirus 3A and 3AB proteins and the functional effect of 3A/3AB membrane association upon RNA replication. Biochemistry 46:5185-99
Buchanan, Susan K; Lukacik, Petra; Grizot, Sylvestre et al. (2007) Structure of colicin I receptor bound to the R-domain of colicin Ia: implications for protein import. EMBO J 26:2594-604
White, Dawn; Musse, Abdiwahab A; Wang, Jie et al. (2006) Toward elucidating the membrane topology of helix two of the colicin E1 channel domain. J Biol Chem 281:32375-84
Wu, Zhengyan; Jakes, Karen S; Samelson-Jones, Ben S et al. (2006) Protein translocation by bacterial toxin channels: a comparison of diphtheria toxin and colicin Ia. Biophys J 91:3249-56
Wang, Jie; Rosconi, Michael P; London, Erwin (2006) Topography of the hydrophilic helices of membrane-inserted diphtheria toxin T domain: TH1-TH3 as a hydrophilic tether. Biochemistry 45:8124-34
Zhao, Gang; London, Erwin (2006) An amino acid ""transmembrane tendency"" scale that approaches the theoretical limit to accuracy for prediction of transmembrane helices: relationship to biological hydrophobicity. Protein Sci 15:1987-2001
Musse, Abdiwahab A; Wang, Jie; Deleon, Gladys P et al. (2006) Scanning the membrane-bound conformation of helix 1 in the colicin E1 channel domain by site-directed fluorescence labeling. J Biol Chem 281:885-95
Zhao, Gang; London, Erwin (2005) Behavior of diphtheria toxin T domain containing substitutions that block normal membrane insertion at Pro345 and Leu307: control of deep membrane insertion and coupling between deep insertion of hydrophobic subdomains. Biochemistry 44:4488-98

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