Positional isotope exchange analysis of the pantothenate synthetase reaction

LaKenya WilliamsFrank M Raushel


Pantothenate synthetase from Mycobacterium tuberculosis catalyzes the formation of pantothenate from ATP, D-pantoate, and beta-alanine. The formation of a kinetically competent pantoyl-adenylate intermediate was established by the observation of a positional isotope exchange (PIX) reaction within (18)O-labeled ATP in the presence of d-pantoate. When [betagamma-(18)O(6)]-ATP was incubated with pantothenate synthetase in the presence of d-pantoate, an (18)O label gradually appeared in the alphabeta-bridge position from both the beta- and the gamma-nonbridge positions. The rates of these two PIX reactions were followed by (31)P NMR spectroscopy and found to be identical. These results are consistent with the formation of enzyme-bound pantoyl-adenylate and pyrophosphate upon the mixing of ATP, D-pantoate, and enzyme. In addition, these results require the complete torsional scrambling of the two phosphoryl groups of the labeled pyrophosphate product. The rate of the PIX reaction increased as the D-pantoate concentration was elevated and then decreased to zero at saturating levels of D-pantoate. These inhibition results support the ordered binding of ATP and D-pantoate to the enzyme active site. The PIX reaction was abolished with t...Continue Reading

Related Concepts

Pantoate-beta-alanine ligase
Adenosine Triphosphate, Chromium Ammonium Salt
Isotope Labeling, Stable
Mycobacterium tuberculosis H37Rv
In Vivo NMR Spectroscopy
Oxygen Isotopes
Peptide synthase
Potassium Compounds

Trending Feeds


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.

Synthetic Genetic Array Analysis

Synthetic genetic arrays allow the systematic examination of genetic interactions. Here is the latest research focusing on synthetic genetic arrays and their analyses.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

Computational Methods for Protein Structures

Computational methods employing machine learning algorithms are powerful tools that can be used to predict the effect of mutations on protein structure. This is important in neurodegenerative disorders, where some mutations can cause the formation of toxic protein aggregations. This feed follows the latests insights into the relationships between mutation and protein structure leading to better understanding of disease.

Congenital Hyperinsulinism

Congenital hyperinsulinism is caused by genetic mutations resulting in excess insulin secretion from beta cells of the pancreas. Here is the latest research.

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.

Epigenetic Memory

Epigenetic memory refers to the heritable genetic changes that are not explained by the DNA sequence. Find the latest research on epigenetic memory here.

Cell Atlas of the Human Eye

Constructing a cell atlas of the human eye will require transcriptomic and histologic analysis over the lifespan. This understanding will aid in the study of development and disease. Find the latest research pertaining to the Cell Atlas of the Human Eye here.

Femoral Neoplasms

Femoral Neoplasms are bone tumors that arise in the femur. Discover the latest research on femoral neoplasms here.