Aspartate 221 of thymidylate synthase is involved in folate cofactor binding and in catalysis

Biochemistry
G Chiericatti, D V Santi

Abstract

Structural studies indicate that Asp 221 of Lactobacilluscasei thymidylate synthase forms a hydrogen bond network with the 2-amino and 3-imino groups of the folate [Matthews, D. A. (1990) J. Mol. Biol. 214, 937-948; Finer-Moore, J. S. (1990)Biochemistry 29, 6977-6986] that has been proposed to participate in catalysis. We prepared a complete replacement set of 19 mutants at position 221 of L. casei thymidylate synthase. Of these, the only one with sufficient activity to complement growth of a thymidylate synthase-deficient host was the Cys mutant. To further elucidate the function of the Asp 221 side chain, seven thymidylate synthase 221 mutants were studied in detail with regard to catalysis of dTMP formation and of thymidylate synthase partial reactions. Most of the mutants bound the nucleotide substrate dUMP with only moderate loss of binding affinity, indicating that the Asp side chain does not contribute to dUMP binding. Most of the mutants catalyzed the cofactor-independent dehalogenation of 5-bromodUMP; hence, the Asp side chain of TS is not essential for addition of the catalytic Cys residue to the nucleotide substrate. Mutants showed decreased affinity for the folate cofactor, but those with side chains capable of hydr...Continue Reading

References

Jan 1, 1995·Annual Review of Biochemistry·C W Carreras, D V Santi

❮ 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.