Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 4 October 1991:
Vol. 254. no. 5028, pp. 109 - 111
DOI: 10.1126/science.1718037
Prev | Table of Contents | Next

Articles

Science, Vol 254, Issue 5028, 109-111
Copyright © 1991 by American Association for the Advancement of Science

articles

A bacterial system for investigating transport effects of cystic fibrosis--associated mutations

AL Gibson, LM Wagner, FS Collins, and DL Oxender

Department of Biological Chemistry, University of Michigan, Ann Arbor 48109.

LIV-I, a high-affinity system that transports neutral, branched-chain amino acids into Escherichia coli, has two components, LivG and LivF, that are homologous to the cystic fibrosis (CF) transmembrane conductance regulator (CFTR). CF-associated mutations of human CFTR were introduced into corresponding regions of LivG, and their effects on leucine transport could be grouped into three classes. Mutations were found that (i) abolished LIV-I--directed transport, (ii) retained about a quarter of wild-type activity at the Michaelis-Menten constant (KM), and (iii) had minimal activity at the KM. A mutation equivalent to a benign polymorphism had no effect on transport. The correlation of these mutational phenotypes in LivG and CFTR suggests that the LIV-I prokaryotic transporter is functionally similar to the CF protein and that this similarity can be exploited to clarify the properties of the nucleotide-binding fold in this superfamily of proteins.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Mutations in the Nucleotide Binding Domain 1 Signature Motif Region Rescue Processing and Functional Defects of Cystic Fibrosis Transmembrane Conductance Regulator Delta F508.
A. C. V. deCarvalho, L. J. Gansheroff, and J. L. Teem (2002)
J. Biol. Chem. 277, 35896-35905
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)