202326-53-2Relevant academic research and scientific papers
Fungal Dioxygenase AsqJ Is Promiscuous and Bimodal: Substrate-Directed Formation of Quinolones versus Quinazolinones
Einsiedler, Manuel,Jamieson, Cooper S.,Maskeri, Mark A.,Houk, Kendall N.,Gulder, Tobias A. M.
supporting information, p. 8297 - 8302 (2021/03/01)
Previous studies showed that the FeII/α-ketoglutarate dependent dioxygenase AsqJ induces a skeletal rearrangement in viridicatin biosynthesis in Aspergillus nidulans, generating a quinolone scaffold from benzo[1,4]diazepine-2,5-dione substrates. We report that AsqJ catalyzes an additional, entirely different reaction, simply by a change in substituent in the benzodiazepinedione substrate. This new mechanism is established by substrate screening, application of functional probes, and computational analysis. AsqJ excises H2CO from the heterocyclic ring structure of suitable benzo[1,4]diazepine-2,5-dione substrates to generate quinazolinones. This novel AsqJ catalysis pathway is governed by a single substituent within the complex substrate. This unique substrate-directed reactivity of AsqJ enables the targeted biocatalytic generation of either quinolones or quinazolinones, two alkaloid frameworks of exceptional biomedical relevance.
Evaluation of dihedral angles of peptides using IR bands of two successive isotope labeled residues
Okabe, Hitomi,Miyata, Daisuke,Nakabayashi, Takakazu,Hiramatsu, Hirotsugu
, p. 80 - 86 (2019/01/28)
The infrared (IR) absorption bands due to peptide bonds (amide bands) have long been used to determine the secondary structure of a peptide and to analyze intra- and intermolecular interactions between amides. In the present study, the dihedral angles of a residue in peptides have also been evaluated using the amide I IR band of two successive residues with isotope labeling. The two successive residues labeled with the13C and18O isotopes give the doublet amide I IR band and the intensity ratio (Rint) and the difference in peak position (|ν) of the doublet band were analyzed using GF matrix and ab initio molecular orbital calculations. We obtained the two-dimensional calculation maps of Rint and |ν against the two dihedral angles. The crossing point of the curves of Rint and |ν is the two dihedral angles of the measured residue. The evaluated dihedral angles of the simple peptides are compared with the reported values. We discuss the limitation and the application of the present method to biopolymers from the obtained results.
A simple and economical method for the production of13C, 18O-labeled fmoc-amino acids with high levels of enrichment: Applications to isotope-edited IR studies of proteins
Marecek, James,Song, BenBen,Brewery, Scott,Belyea, Jenifer,Dyer, R. Brian,Raleigh, Daniel P.
, p. 4935 - 4938 (2008/03/28)
Isotope-edited IR of proteins has generated considerable interest. Double labeling with 13C and 18O with high levels of isotopic enrichment is required for residue-specific resolution. Current methods for the preparation of doubly la
