The role of the single tryptophan residue in the structure and function of ribonuclease T1

Journal of Biochemistry
Y FukunagaK Narita


The previously reported method for the preparation of Kyn 59-RNase T1 and NFK 59-RNase T1 has been improved, and these two proteins have been obtained in high purity. Kyn 59-RNase T1, fully active for the hydrolysis of GpA and GpC, emitted a 35-fold-enhanced fluorescence of kynurenine relative to acetylnurenine amide with an emission maximum at 455 nm upon excitation at 380 nm. The polarity of the environment of Kyn 59 estimated from the emission maximum corresponded to a dielectric constant of 6. Upon excitation at 325 nm, NFK 59-RNase T1, less active than Kyn 59-RNase T1, exhibited a quenched N'-formylkynurenine fluorescence with an emission maximum at 423 nm, from which the value of 12 was obtained as the dielectric constant of the surroundings of residue 59. In both modified proteins, distinct tyrosine fluorescence appeared on excitation at 280 nm. The detection of an energy transfer from tyrosine to residue 59 suggests that the tertiary structure is very similar in Kyn 59-RNase T1 and native RNase T1. With guanidine hydrochloride, Kyn 59-RNase T1 was less stable than the native protein. Carboxymethylation at Glu 58 was shown to stabilize the active site of the modified enzyme. Based on the information collected for Kyn 59-...Continue Reading

Related Concepts

N'-formylkynurenine, (S)-isomer
Ribonuclease F2
Plasma Protein Binding Capacity
Alkaline Ribonuclease
Fluorescence Spectroscopy
Guanidine Sulfite (1: 1)

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.

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.

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.

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.

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.