The regulation of transmembrane ion critical is critical for many cell functions. Unfortunately, the mechanisms leading to ion transport are poorly understood at the molecular level. In part, this is due to the difficulty in determining the structure of large intrinsic membrane ion channels. To overcome this difficulty, small structure that are approachable with a number of synthetic and spectroscopic methodologies will be examine. The mechanisms of ion transport through two simple channels will be investigated: the polyene macrolide amphotericin B and the linear peptide alamethicin. Amphotericin B is a chemotherapy, and is also reported to have activity against the human immunodeficiency virus (HV). Alamethicin is a small peptide that produces a voltage- dependent conductance in model membranes. In addition to these two channels, a number of synthetic peptides will be investigate to determine the role that electrostatic interactions have in protein binding and conformation in membranes. The overall objectives of this work are to elucidate fundamental molecular features that are important in promoting ion conduction, voltage-dependence and protein binding in membranes. Through the investigation of these simple systems, insight into the operation of larger, intrinsic ion channels will be obtained. New approaches to investigate protein - membrane interactions will be developed that should have general utility. It is also anticipated that insight into the antifungal and toxic effects of amphotericin B will be obtained.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM035215-05
Application #
3287584
Study Section
Biophysical Chemistry Study Section (BBCB)
Project Start
1985-09-06
Project End
1994-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Virginia
Department
Type
Schools of Arts and Sciences
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Sarver, Jessica L; Zhang, Michael; Liu, Lishan et al. (2018) A Dynamic Protein-Protein Coupling between the TonB-Dependent Transporter FhuA and TonB. Biochemistry 57:1045-1053
Sikora, Arthur; Joseph, Benesh; Matson, Morgan et al. (2016) Allosteric Signaling Is Bidirectional in an Outer-Membrane Transport Protein. Biophys J 111:1908-1918
Joseph, Benesh; Sikora, Arthur; Cafiso, David S (2016) Ligand Induced Conformational Changes of a Membrane Transporter in E. coli Cells Observed with DEER/PELDOR. J Am Chem Soc 138:1844-7
Joseph, Benesh; Sikora, Arthur; Bordignon, Enrica et al. (2015) Distance Measurement on an Endogenous Membrane Transporter in E. coli Cells and Native Membranes Using EPR Spectroscopy. Angew Chem Int Ed Engl 54:6196-9
Iyalomhe, Osigbemhe; Herrick, Dawn Z; Cafiso, David S et al. (2014) Closure of the cytoplasmic gate formed by TM5 and TM11 during transport in the oxalate/formate exchanger from Oxalobacter formigenes. Biochemistry 53:7735-44
Cafiso, David S (2014) Identifying and quantitating conformational exchange in membrane proteins using site-directed spin labeling. Acc Chem Res 47:3102-9
Freed, Daniel M; Lukasik, Stephen M; Sikora, Arthur et al. (2013) Monomeric TonB and the Ton box are required for the formation of a high-affinity transporter-TonB complex. Biochemistry 52:2638-48
Regan, Michael C; Horanyi, Peter S; Pryor Jr, Edward E et al. (2013) Structural and dynamic studies of the transcription factor ERG reveal DNA binding is allosterically autoinhibited. Proc Natl Acad Sci U S A 110:13374-9
Flores Jiménez, Ricardo H; Cafiso, David S (2012) The N-terminal domain of a TonB-dependent transporter undergoes a reversible stepwise denaturation. Biochemistry 51:3642-50
Cafiso, David S (2012) Taking the pulse of protein interactions by EPR spectroscopy. Biophys J 103:2047-8

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