Control of H+/lactose coupling by ionic interactions in the lactose permease of Escherichia coli

The Journal of Membrane Biology
J L Johnson, Robert J Brooker

Abstract

A combinatorial approach was used to study putative interactions among six ionizable residues (Asp-240, Glu-269, Arg-302, Lys-319, His-322, and Glu-325) in the lactose permease. Neutral mutations were made involving five ion pairs that had not been previously studied. Double mutants, R302L/E325Q and D240N/H322Q, had moderate levels of downhill [(14)C]-lactose transport. Mutants in which only one of these six residues was left unchanged (pentuple mutants) were also made. A Pent269(-) mutant (in which only Glu-269 remains) catalyzed a moderate level of downhill lactose transport. Pent240(-) and Pent 322(+) also showed low levels of downhill lactose transport. Additionally, a Pent240(-) mutant exhibited proton transport upon addition of melibiose, but not lactose. This striking result demonstrates that neutralization of up to five residues of the lactose permease does not abolish proton transport. A mutant with neutral replacements at six ionic residues (hextuple mutant) had low levels of downhill lactose transport, but no uphill accumulation or proton transport. Since none of the mutants in this study catalyzes active accumulation of lactose, this is consistent with other reports that have shown that each residue is essential for...Continue Reading

References

Feb 27, 1978·Molecular & General Genetics : MGG·R M TeatherP Overath
Nov 1, 1992·Proceedings of the National Academy of Sciences of the United States of America·M Sahin-TóthH R Kaback
Jan 30, 1990·Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences·H R Kaback
Jul 1, 1990·Proceedings of the National Academy of Sciences of the United States of America·J Calamia, C Manoil
Mar 1, 1990·Research in Microbiology·M C BotfieldT H Wilson
Jun 1, 1985·Proceedings of the National Academy of Sciences of the United States of America·R J Brooker, T H Wilson
Mar 1, 1973·The Biochemical Journal·I C West, P Mitchell
Nov 9, 1970·Biochemical and Biophysical Research Communications·I C West
Oct 26, 1982·Biochemistry·D L FosterH R Kaback
Feb 7, 1980·Nature·D E BüchelB Müller-Hill
Mar 1, 1995·Protein Science : a Publication of the Protein Society·V C Goswitz, R J Brooker
Jan 1, 1994·Molecular Membrane Biology·M L UjwalH R Kaback
Apr 8, 1998·Microbiology and Molecular Biology Reviews : MMBR·S S PaoM H Saier
May 17, 2001·Proceedings of the National Academy of Sciences of the United States of America·M Sahin-Toth, H R Kaback
Jun 23, 2001·The Journal of Membrane Biology·J L JohnsonR J Brooker
Jun 29, 2001·Seminars in Cell & Developmental Biology·M H Saier, I T Paulsen
Jan 29, 2003·Biochemistry·Jerry L Johnson, Robert J Brooker

❮ Previous
Next ❯

Citations

Aug 23, 2008·Journal of Molecular Biology·Ioannis PapageorgiouGeorge Diallinas
Nov 22, 2017·Applied Microbiology and Biotechnology·David J WurmOliver Spadiut
Feb 28, 2007·Biophysical Journal·Richard J NaftalinPhilip Cunningham
Jul 20, 2007·Structure·John Holyoake, Mark S P Sansom
Oct 30, 2010·Biochimica Et Biophysica Acta·Lucy R ForrestChristine Ziegler

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.

Related Papers

Annual Review of Biophysics and Biomolecular Structure
Lan Guan, H R Kaback
Proceedings of the National Academy of Sciences of the United States of America
M Sahin-TóthH R Kaback
© 2022 Meta ULC. All rights reserved