scholarly journals Structural diversity and phylogenetic distribution of valyl tRNA-like structures in viruses

RNA ◽  
2020 ◽  
Vol 27 (1) ◽  
pp. 27-39
Author(s):  
Madeline E. Sherlock ◽  
Erik W. Hartwick ◽  
Andrea MacFadden ◽  
Jeffrey S. Kieft
Author(s):  
Madeline E. Sherlock ◽  
Erik W. Hartwick ◽  
Andrea MacFadden ◽  
Jeffrey S. Kieft

ABSTRACTViruses commonly use specifically folded RNA elements that interact with both host and viral proteins to perform functions important for diverse viral processes. Examples are found at the 3′ termini of certain positive-sense ssRNA virus genomes where they partially mimic tRNAs, including being aminoacylated by host cell enzymes. Valine-accepting tRNA-like structures (TLSVal) are an example that share some clear homology to canonical tRNAs but have several important structural differences. Although many examples of TLSVal have been identified, we lacked a full understanding of their structural diversity and phylogenetic distribution. To address this, we undertook an in-depth bioinformatic and biochemical investigation of these RNAs, guided by recent high-resolution structures of a TLSVal. We cataloged many new examples in plant-infecting viruses but also in unrelated insect-specific viruses. Using biochemical and structural approaches, we verified the secondary structure of representative TLSVal substrates and tested their ability to be valylated, finding structural heterogeneity within this class. In a few cases, large stem-loop structures are inserted within distinct variable regions located in an area of the TLS distal to known host cell factor binding sites. In addition, we identified one virus whose TLS has switched its anticodon away from valine; the implications of this remain unclear. These results refine our understanding of the structural and functional mechanistic details of tRNA mimicry and how this may be used in viral infection.


2016 ◽  
Vol 18 (12) ◽  
pp. 4697-4709 ◽  
Author(s):  
Bruno C. Marreiros ◽  
Filipa V. Sena ◽  
Filipe M. Sousa ◽  
Ana P. Batista ◽  
Manuela M. Pereira

2020 ◽  
Author(s):  
Dung Do

<p>Chiral molecules with their defined 3-D structures are of paramount importance for the study of chemical biology and drug discovery. Having rich structural diversity and unique stereoisomerism, chiral molecules offer a large chemical space that can be explored for the design of new therapeutic agents.<sup>1</sup> Practically, chiral architectures are usually prepared from organometallic and organocatalytic processes where a transition metal or an organocatalyst is tailor-made for desired reactions. As a result, developing a method that enables rapid assembly of chiral complex molecules under metal- and organocatalyst-free condition represents a daunting challenge. Here we developed a straightforward route to create a chiral 3-D structure from 2-D structures and an amino acid without any chiral catalyst. The center of this research is the design of a <a>special chiral spiroimidazolidinone cyclohexadienone intermediate</a>, a merger of a chiral reactive substrate with multiple nucleophillic/electrophillic sites and a transient organocatalyst. <a>This unique substrate-catalyst (“subcatalyst”) dual role of the intermediate enhances </a><a>the coordinational proximity of the chiral substrate and catalyst</a> in the key Aza-Michael/Michael cascade resulting in a substantial steric discrimination and an excellent overall diastereoselectivity. Whereas the “subcatalyst” (hidden catalyst) is not present in the reaction’s initial components, which renders a chiral catalyst-free process, it is strategically produced to promote sequential self-catalyzed reactions. The success of this methodology will pave the way for many efficient preparations of chiral complex molecules and aid for the quest to create next generation of therapeutic agents.</p>


2018 ◽  
Vol 25 (18) ◽  
pp. 2140-2165 ◽  
Author(s):  
Jelena B. Popovic-Djordjevic ◽  
Ivana I. Jevtic ◽  
Tatjana P. Stanojkovic

Background: Diabetes mellitus type 2 (DMT2) is an endocrine disease of global proportions which is currently affecting 1 in 12 adults in the world, with still increasing prevalence. World Health Organization (WHO) declared this worldwide health problem, as an epidemic disease, to be the only non-infectious disease with such categorization. People with DMT2 are at increased risk of various complications and have shorter life expectancy. The main classes of oral antidiabetic drugs accessible today for DMT2 vary in their chemical composition, modes of action, safety profiles and tolerability. Methods: A systematic search of peer-reviewed scientific literature and public databases has been conducted. We included the most recent relevant research papers and data in respect to the focus of the present review. The quality of retrieved papers was assessed using standard tools. Results: The review highlights the chemical structural diversity of the molecules that have the common target-DMT2. So-called traditional antidiabetics as well as the newest and the least explored drugs include polypeptides and amino acid derivatives (insulin, glucagon-like peptide 1, dipeptidyl peptidase-IV inhibitors, amylin), sulfonylurea derivatives, benzylthiazolidine- 2,4-diones (peroxisome proliferator activated receptor-γ agonists/glitazones), condensed guanido core (metformin) and sugar-like molecules (α-glucosidase and sodium/ glucose co-transporter 2 inhibitors). Conclusion: As diabetes becomes a more common disease, interest in new pharmacological targets is on the rise.


2018 ◽  
Vol 25 (31) ◽  
pp. 3748-3767 ◽  
Author(s):  
Mohammed Benabdallah ◽  
Oualid Talhi ◽  
Fatiha Nouali ◽  
Nouredine Choukchou-Braham ◽  
Khaldoun Bachari ◽  
...  

The present review deals with the progress in medicinal chemistry of spirocyclic compounds, a wider class of natural and synthetic organic molecules, defined as a hybrid of two molecular entities covalently linked via a unique tetrahedral carbon. This spiro central carbon confers to the molecules a tridimensional structurally oriented framework, which is found in many medicinally relevant compounds, a well-known example is the antihypertensive spironolactone. Various bioactive natural products possess the privileged spiro linkage and different chemo-types thereof become synthetically accessible since the 20th century. Actually, there has been a growing interest in the synthesis of heterocyclic hybrids gathered via a spiro carbon. Most of these combinations are two moieties in one scaffold being able to interfere with biological systems through sequential mechanisms. Spirocyclic hybrids containing indole or oxindole units are compounds exhibiting higher interaction with biological receptors by protein inhibition or enzymatic pathways and their recognition as promising anticancer agents in targeted chemotherapy is foreseen. These specific, low-weight and noncomplex spirocyclic hybrids are potent inhibitors of SIRT1, Mdm2–p53 and PLK4, showing affinity for anaplastic lymphoma kinase (ALK) receptor. They are also known as excellent DNA binders, acting on cellular division by arresting the cell cycle at different phases and inducing apoptotic cell death. A structural diversity of spirocyclic hybrids has proved neuroprotective effects, anti-HIV, antiviral and antibacterial activities. Hundred of papers are mentioned in this review underlying chemical issues and pharmacological potencies of spiro compounds, which render them impressive synthetic hits for innovative drug conception.


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