Table of Contents
Computational Biology Journal
Volume 2013 (2013), Article ID 938169, 9 pages
Research Article

Graph-Theoretic Models of Mutations in the Nucleotide Binding Domain 1 of the Cystic Fibrosis Transmembrane Conductance Regulator

1Department of Mathematics and Statistics, East Tennessee State University, Johnson City, TN 37614, USA
2Institute for Quantitative Biology, East Tennessee State University, Johnson City, TN 37614, USA

Received 30 November 2012; Revised 12 March 2013; Accepted 12 March 2013

Academic Editor: Alessandra Lumini

Copyright © 2013 Debra J. Knisley et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Cystic fibrosis is one of the most common inherited diseases and is caused by a mutation in a membrane protein, the cystic fibrosis transmembrane conductance regulator (CFTR). This protein serves as a chloride channel and regulates the viscosity of mucus lining the ducts of a number of organs. Although much has been learned about the consequences of mutations on the energy landscape and the resulting disrupted folding pathway of CFTR, a level of understanding needed to correct the misfolding has not been achieved. The most common mutations of CFTR are located in one of two nucleotide binding domains, namely, the nucleotide binding domain 1 (NBD1). We model NBD1 using a nested graph model. The vertices in the lowest layer each represent an atom in the structure of an amino acid residue, while the vertices in the mid layer each represent the residue. The vertices in the top layer each represent a subdomain of the nucleotide binding domain. We use this model to quantify the effects of a single point mutation on the protein domain. We compare the wildtype structure with eight of the most common mutations. The graph-theoretic model provides insight into how a single point mutation can have such profound structural consequences.