Biomaterial Database

Nucleoside selectivity of Aspergillus fumigatus nucleoside-diphosphate kinase. 2021

Stephanie Nguyen, and Blagojce Jovcevski, and Tara L Pukala, and John B Bruning

Institute of Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Australia.

Aspergillus fumigatus infections are rising at a disconcerting rate in tandem with antifungal resistance rates. Efforts to develop novel antifungals have been hindered by the limited knowledge of fundamental biological and structural mechanisms of A. fumigatus propagation. Biosynthesis of NTPs, the building blocks of DNA and RNA, is catalysed by NDK. An essential enzyme in A. fumigatus, NDK poses as an attractive target for novel antifungals. NDK exhibits broad substrate specificity across species, using both purines and pyrimidines, but the selectivity of such nucleosides in A. fumigatus NDK is unknown, impeding structure-guided inhibitor design. Structures of NDK in unbound- and NDP-bound states were solved, and NDK activity was assessed in the presence of various NTP substrates. We present the first instance of a unique substrate binding mode adopted by CDP and TDP specific to A. fumigatus NDK that illuminates the structural determinants of selectivity. Analysis of the oligomeric state reveals that A. fumigatus NDK adopts a hexameric assembly in both unbound- and NDP-bound states, contrary to previous reports suggesting it is tetrameric. Kinetic analysis revealed that ATP exhibited the greatest turnover rate (321 ± 33.0 s-1 ), specificity constant (626 ± 110.0 mm-1 ·s-1 ) and binding free energy change (-37.0 ± 3.5 kcal·mol-1 ). Comparatively, cytidine nucleosides displayed the slowest turnover rate (53.1 ± 3.7 s-1 ) and lowest specificity constant (40.2 ± 4.4 mm-1 ·s-1 ). We conclude that NDK exhibits nucleoside selectivity whereby adenine nucleosides are used preferentially compared to cytidine nucleosides, and these insights can be exploited to guide drug design. ENZYMES: Nucleoside-diphosphate kinase (EC 2.7.4.6). DATABASE: Structural data are available in the PDB database under the accession numbers: Unbound-NDK (6XP4), ADP-NDK (6XP7), GDP-NDK (6XPS), IDP-NDK (6XPU), UDP-NDK (6XPT), CDP-NDK (6XPW), TDP-NDK (6XPV).

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009701	Nucleoside-Diphosphate Kinase	An enzyme that is found in mitochondria and in the soluble cytoplasm of cells. It catalyzes reversible reactions of a nucleoside triphosphate, e.g., ATP, with a nucleoside diphosphate, e.g., UDP, to form ADP and UTP. Many nucleoside diphosphates can act as acceptor, while many ribo- and deoxyribonucleoside triphosphates can act as donor. EC 2.7.4.6.	Deoxynucleoside Diphosphate Kinases,GDP Kinase,Nucleoside Diphosphokinases,Nucleoside-Diphosphate Kinases,Diphosphate Kinases, Deoxynucleoside,Diphosphokinases, Nucleoside,Kinase, GDP,Kinase, Nucleoside-Diphosphate,Kinases, Deoxynucleoside Diphosphate,Kinases, Nucleoside-Diphosphate,Nucleoside Diphosphate Kinase,Nucleoside Diphosphate Kinases
D009705	Nucleosides	Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleoside,Nucleoside Analog,Nucleoside Analogs,Analog, Nucleoside,Analogs, Nucleoside
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001228	Aspergillosis	Infections with fungi of the genus ASPERGILLUS.	Aspergillus Infection,Aspergilloses,Aspergillus Infections,Infection, Aspergillus,Infections, Aspergillus
D001232	Aspergillus fumigatus	A species of imperfect fungi from which the antibiotic fumigatin is obtained. Its spores may cause respiratory infection in birds and mammals.	Aspergillus fumigates,Neosartorya fumigata,Sartorya fumigata
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities