Mutations in the A subunit affect yield, stability, and protease sensitivity of nontoxic derivatives of heat-labile enterotoxin.

Infection and Immunity
C MagagnoliM Pizza

Abstract

Heat-labile toxin (LT) is a protein related to cholera toxin, produced by enterotoxigenic Escherichia coli strains, that is organized as an AB5 complex. A number of nontoxic derivatives of LT, useful for new or improved vaccines against diarrheal diseases or as mucosal adjuvants, have been constructed by site-directed mutagenesis. Here we have studied the biochemical properties of the nontoxic mutants LT-K7 (Arg-7-->Lys), LT-D53 (Val-53-->Asp), LT-K63 (Ser-63-->Lys), LT-K97 (Val-97-->Lys), LT-K104 (Tyr-104-->Lys), LT-K114 (Ser-114-->Lys), and LT-K7/K97 (Arg-7-->Lys and Val-97-->Lys). We have found that mutations in the A subunit may have profound effects on the ability to form the AB5 structure and on the stability and trypsin sensitivity of the purified proteins. Unstable mutants, during long-term storage at 4 degrees C, showed a decrease in the amount of the assembled protein in solution and a parallel appearance of soluble monomeric B subunit. This finding suggests that the stability of the B pentamer is influenced by the A subunit which is associated with it. Among the seven nontoxic mutants tested, LT-K63 was found to be efficient in AB5 production, extremely stable during storage, resistant to proteolytic attack, and very...Continue Reading

References

Dec 15, 1992·Proceedings of the National Academy of Sciences of the United States of America·S J StreatfieldT R Hirst
Dec 1, 1991·Molecular Microbiology·R E Dalbey
Feb 7, 1989·Biochemistry·L M Gierasch
Oct 1, 1988·Proceedings of the National Academy of Sciences of the United States of America·S J HardyT R Hirst
Apr 1, 1967·The Journal of Pathology and Bacteriology·H W Smith, S Halls
Oct 1, 1969·The Journal of Infectious Diseases·C L Gyles, D A Barnum
Jul 1, 1980·Infection and Immunity·J D ClementsR A Finkelstein
Dec 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·T R HirstJ Holmgren
Jan 1, 1981·Proceedings of the National Academy of Sciences of the United States of America·E K SpicerD E Schafer
Feb 28, 1995·Proceedings of the National Academy of Sciences of the United States of America·G DouceG Dougan

❮ Previous
Next ❯

Citations

Apr 15, 2011·The Journal of Immunology : Official Journal of the American Association of Immunologists·Corinna F BreretonKingston H G Mills
Oct 28, 1998·Molecular Aspects of Medicine·G Del GiudiceR Rappuoli
May 20, 1998·Research in Immunology·N Lycke
Mar 1, 2005·Vaccine·L C Freytag, J D Clements

❮ 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.