The ATP-binding cassette (ABC) superfamily is one of the largest and most highly conserved class of integral membrane proteins and is involved in the ATP-dependent transport of solutes across cellular membranes. Prominent members in this family include P-glycoprotein linked to multidrug resistance to chemotherapy for cancers and the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), a chloride channel whose malfunction causes cystic fibrosis, the most common lethal genetic disease in Caucasians. One unique feature of CFTR is that it has two distinct nucleotide binding domains (NBDs) that play critical roles in the gating of CFTR channels. Our understanding of the molecular basis of the regulation mechanisms, however, remains primitive. Unresolved questions include: What is the functional role of the individual NBD? Which NBD opens the channel, and which NBD closes the channel? How do the two NBDs interact with each other? Do they form a dimeric structure? If yes, does this dimeric structure depend on the state of the channel? These are the fundamental questions that interest a broad spectrum of biologists. A quantitative, multi-disciplinary approach will be used to tackle the molecular mechanisms whereby CFTR gating is regulated. It is a combination of structural modeling, energetic studies, patch-clamp recordings, biochemical assays and chemical synthesis. We plan to investigate quantitatively the functional roles of NBDs in the gating of CFTR channels. The two parallel aims in this project are:
Aim 1. To engineer the nucleotide-binding pockets of CFTR to distinguish the functional roles of the NBDs.
Aim 2. To investigate the hetero-dimeric structure of the NBD complex. A clear understanding of the quantitative mechanisms of the functions of CFTR is essential to future therapeutic design for CFTR-related diseases such as cystic fibrosis and secretory diarrhea. The methods as well as the results are directly applicable; to quantitative structure-function studies on other ABC transporter proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Mentored Quantitative Research Career Development Award (K25)
Project #
5K25DK061529-02
Application #
6623422
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Hyde, James F
Project Start
2002-06-01
Project End
2007-05-31
Budget Start
2003-06-01
Budget End
2004-05-31
Support Year
2
Fiscal Year
2003
Total Cost
$108,226
Indirect Cost
Name
University of Missouri-Columbia
Department
Type
Organized Research Units
DUNS #
153890272
City
Columbia
State
MO
Country
United States
Zip Code
65211
Huang, Sheng-You; Bolser, Diana; Liu, Hao-Yang et al. (2009) Molecular modeling of the heterodimer of human CFTR's nucleotide-binding domains using a protein-protein docking approach. J Mol Graph Model 27:822-8
Liu, Hao-Yang; Grinter, Sam Z; Zou, Xiaoqin (2009) Multiscale generalized born modeling of ligand binding energies for virtual database screening. J Phys Chem B 113:11793-9
Yu, Tao; Zou, Xiaoqin; Huang, Sheng-You et al. (2009) Cutoff variation induces different topological properties: a new discovery of amino acid network within protein. J Theor Biol 256:408-13
Huang, Sheng-You; Zou, Xiaoqin (2008) An iterative knowledge-based scoring function for protein-protein recognition. Proteins 72:557-79
Huang, Sheng-You; Zou, Xiaoqin (2007) Efficient molecular docking of NMR structures: application to HIV-1 protease. Protein Sci 16:43-51
Huang, Sheng-You; Zou, Xiaoqin (2007) Ensemble docking of multiple protein structures: considering protein structural variations in molecular docking. Proteins 66:399-421
Huang, Sheng-You; Zou, Xiaoqin (2006) An iterative knowledge-based scoring function to predict protein-ligand interactions: I. Derivation of interaction potentials. J Comput Chem 27:1866-75
Liu, Hao-Yang; Zou, Xiaoqin (2006) Electrostatics of ligand binding: parametrization of the generalized Born model and comparison with the Poisson-Boltzmann approach. J Phys Chem B 110:9304-13
Zhou, Zhen; Wang, Xiaohui; Liu, Hao-Yang et al. (2006) The two ATP binding sites of cystic fibrosis transmembrane conductance regulator (CFTR) play distinct roles in gating kinetics and energetics. J Gen Physiol 128:413-22
Gatto, Craig; Helms, Jeff B; Prasse, Megan C et al. (2006) Similarities and differences between organic cation inhibition of the Na,K-ATPase and PMCA. Biochemistry 45:13331-45

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