This research is focused on understanding the basic chemical mechanisms by which K+ channel proteins work. Near atomic-resolution structures are emerging for ion channels and for isolated domains thereof, and this work will exploit our new knowledge of these structures in asking questions about K+ channel mechanisms. In particular, the proposed work is aimed at two K+ channels - the bacterial channel KcsA, which has produced unprecedented insight into the chemistry of ion selectivity, and Shaker, a well-studied """"""""Kv""""""""-type channel representative of many homologous channels in the nervous system. KcsA may be expressed at high levels and studied in biochemically defined, purified systems. We will lay out the basic ion permeation properties of KcsA by recording single channels in reconstituted membranes. Using this system, we will examine the reasons for the odd shape of the permeation pathway, focusing particularly on the electrostatics of ion transport. We will use magnetic resonance methods to directly measure binding of ions to the pore. In addition, we will attempt to understand the molecular architecture of Shaker K+ channels by a combination of techniques designed to measure distances between specific regions of the channel. This research is not directed towards any particular disease-related problem; it is the central roles that K+ channels play in virtually all human physiology that make this basic research relevant to human health in general.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031768-22
Application #
6727479
Study Section
Special Emphasis Panel (ZRG1-MDCN-3 (01))
Program Officer
Shapiro, Bert I
Project Start
1983-04-01
Project End
2005-12-14
Budget Start
2004-04-01
Budget End
2005-12-14
Support Year
22
Fiscal Year
2004
Total Cost
$250,923
Indirect Cost
Name
Brandeis University
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
616845814
City
Waltham
State
MA
Country
United States
Zip Code
02454
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Robertson, Janice L; Kolmakova-Partensky, Ludmila; Miller, Christopher (2010) Design, function and structure of a monomeric ClC transporter. Nature 468:844-7
Miller, Christopher; Nguitragool, Wang (2009) A provisional transport mechanism for a chloride channel-type Cl-/H+ exchanger. Philos Trans R Soc Lond B Biol Sci 364:175-80
Fang, Yiling; Jayaram, Hariharan; Shane, Tania et al. (2009) Structure of a prokaryotic virtual proton pump at 3.2 A resolution. Nature 460:1040-3
Nguitragool, Wang; Miller, Christopher (2007) Inaugural Article: CLC Cl /H+ transporters constrained by covalent cross-linking. Proc Natl Acad Sci U S A 104:20659-65
Nguitragool, Wang; Miller, Christopher (2006) Uncoupling of a CLC Cl-/H+ exchange transporter by polyatomic anions. J Mol Biol 362:682-90
Accardi, Alessio; Lobet, Severine; Williams, Carole et al. (2006) Synergism between halide binding and proton transport in a CLC-type exchanger. J Mol Biol 362:691-9
Accardi, Alessio; Walden, Michael; Nguitragool, Wang et al. (2005) Separate ion pathways in a Cl-/H+ exchanger. J Gen Physiol 126:563-70
Nimigean, Crina M; Shane, Tania; Miller, Christopher (2004) A cyclic nucleotide modulated prokaryotic K+ channel. J Gen Physiol 124:203-10
Kienker, Paul K; Jakes, Karen S; Blaustein, Robert O et al. (2003) Sizing the protein translocation pathway of colicin Ia channels. J Gen Physiol 122:161-76

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