scholarly journals Erratum: Quantitative functional characterization of conserved molecular interactions in the active site of mannitol 2-dehydrogenase

2016 ◽  
Vol 25 (3) ◽  
pp. 769-770
Author(s):  
James E. Lucas ◽  
Justin B. Siegel
Keyword(s):  
Molecular Interactions ◽  
Active Site ◽  
Functional Characterization

scholarly journals Structural and Functional Characterization of the Human Thymidylate Synthase (hTS) Interface Variant R175C, New Perspectives for the Development of hTS Inhibitors

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1362
Author(s):  
Cecilia Pozzi ◽  
Stefania Ferrari ◽  
Rosaria Luciani ◽  
Maria Costi ◽  
Stefano Mangani
Keyword(s):  
Thymidylate Synthase ◽  
Active Site ◽  
Functional Characterization ◽  
Binding Mode ◽  
Anticancer Chemotherapy ◽  
Innovative Strategies ◽  
X Ray Crystallography ◽  
Site Targeting ◽  
New Strategies

Human thymidylate synthase (hTS) is pivotal for cell survival and proliferation, indeed it provides the only synthetic source of dTMP, required for DNA biosynthesis. hTS represents a validated target for anticancer chemotherapy. However, active site-targeting drugs towards hTS have limitations connected to the onset of resistance. Thus, new strategies have to be applied to effectively target hTS without inducing resistance in cancer cells. Here, we report the generation and the functional and structural characterization of a new hTS interface variant in which Arg175 is replaced by a cysteine. Arg175 is located at the interface of the hTS obligate homodimer and protrudes inside the active site of the partner subunit, in which it provides a fundamental contribution for substrate binding. Indeed, the R175C variant results catalytically inactive. The introduction of a cysteine at the dimer interface is functional for development of new hTS inhibitors through innovative strategies, such as the tethering approach. Structural analysis, performed through X-ray crystallography, has revealed that a cofactor derivative is entrapped inside the catalytic cavity of the hTS R175C variant. The peculiar binding mode of the cofactor analogue suggests new clues exploitable for the design of new hTS inhibitors.

scholarly journals Identification and Functional Characterization of an Active-site Lysine in Mevalonate Kinase

1997 ◽  
Vol 272 (9) ◽  
pp. 5741-5746 ◽  
Author(s):  
David Potter ◽  
Jean M. Wojnar ◽  
Chakravarthy Narasimhan ◽  
Henry M. Miziorko
Keyword(s):  
Active Site ◽  
Functional Characterization ◽  
Mevalonate Kinase

scholarly journals Structural and functional characterization of CMP-N-acetylneuraminate synthetase fromVibrio cholerae

2019 ◽  
Vol 75 (6) ◽  
pp. 564-577
Author(s):  
Sucharita Bose ◽  
Debayan Purkait ◽  
Deepthi Joseph ◽  
Vinod Nayak ◽  
Ramaswamy Subramanian
Keyword(s):  
Sialic Acid ◽  
Vibrio Cholerae ◽  
Active Site ◽  
Drug Targets ◽  
Pathogenic Bacteria ◽  
Pasteurella Multocida ◽  
Bacterial Species ◽  
Functional Characterization ◽  
Gut Colonization

Several pathogenic bacteria utilize sialic acid, including host-derivedN-acetylneuraminic acid (Neu5Ac), in at least two ways: they use it as a nutrient source and as a host-evasion strategy by coating themselves with Neu5Ac. Given the significant role of sialic acid in pathogenesis and host-gut colonization by various pathogenic bacteria, includingNeisseria meningitidis,Haemophilus influenzae,Pasteurella multocidaandVibrio cholerae, several enzymes of the sialic acid catabolic, biosynthetic and incorporation pathways are considered to be potential drug targets. In this work, findings on the structural and functional characterization of CMP-N-acetylneuraminate synthetase (CMAS), a key enzyme in the incorporation pathway, fromVibrio choleraeare reported. CMAS catalyzes the synthesis of CMP-sialic acid by utilizing CTP and sialic acid. Crystal structures of the apo and the CDP-bound forms of the enzyme were determined, which allowed the identification of the metal cofactor Mg2+in the active site interacting with CDP and the invariant Asp215 residue. While open and closed structural forms of the enzyme from eukaryotic and other bacterial species have already been characterized, a partially closed structure ofV. choleraeCMAS (VcCMAS) observed upon CDP binding, representing an intermediate state, is reported here. The kinetic data suggest that VcCMAS is capable of activating the two most common sialic acid derivatives, Neu5Ac and Neu5Gc. Amino-acid sequence and structural comparison of the active site of VcCMAS with those of eukaryotic and other bacterial counterparts reveal a diverse hydrophobic pocket that interacts with the C5 substituents of sialic acid. Analyses of the thermodynamic signatures obtained from the binding of the nucleotide (CTP) and the product (CMP-sialic acid) to VcCMAS provide fundamental information on the energetics of the binding process.

scholarly journals Virus-Encoded Aminoacyl-tRNA Synthetases: Structural and Functional Characterization of Mimivirus TyrRS and MetRS

2007 ◽  
Vol 81 (22) ◽  
pp. 12406-12417 ◽  
Author(s):  
Chantal Abergel ◽  
Joëlle Rudinger-Thirion ◽  
Richard Giegé ◽  
Jean-Michel Claverie
Keyword(s):  
Active Site ◽  
Functional Characterization ◽  
Evolutionary Relationship ◽  
Trna Synthetase ◽  
Dna Viruses ◽  
Trna Synthetases ◽  
Functional Studies ◽  
Aminoacyl Trna Synthetases ◽  
Viral Enzyme

ABSTRACT Aminoacyl-tRNA synthetases are pivotal in determining how the genetic code is translated in amino acids and in providing the substrate for protein synthesis. As such, they fulfill a key role in a process universally conserved in all cellular organisms from their most complex to their most reduced parasitic forms. In contrast, even complex viruses were not found to encode much translation machinery, with the exception of isolated components such as tRNAs. In this context, the discovery of four aminoacyl-tRNA synthetases encoded in the genome of mimivirus together with a full set of translation initiation, elongation, and termination factors appeared to blur what was once a clear frontier between the cellular and viral world. Functional studies of two mimivirus tRNA synthetases confirmed the MetRS specificity for methionine and the TyrRS specificity for tyrosine and conformity with the identity rules for tRNATyr for archea/eukarya. The atomic structure of the mimivirus tyrosyl-tRNA synthetase in complex with tyrosinol exhibits the typical fold and active-site organization of archaeal-type TyrRS. However, the viral enzyme presents a unique dimeric conformation and significant differences in its anticodon binding site. The present work suggests that mimivirus aminoacyl-tRNA synthetases function as regular translation enzymes in infected amoebas. Their phylogenetic classification does not suggest that they have been acquired recently by horizontal gene transfer from a cellular host but rather militates in favor of an intricate evolutionary relationship between large DNA viruses and ancestral eukaryotes.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

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