A living WHO guideline on drugs for covid-19

CITATION: Agarwal, A. et al. 2022. A living WHO guideline on drugs for covid-19. British Medical Journal, 370. doi:10.1136/bmj.m3379The original publication is available at https://jcp.bmj.com/This living guideline by Arnav Agarwal and colleagues (BMJ 2020;370:m3379, doi:10.1136/bmj.m3379) was last updated on 22 April 2022, but the infographic contained two dosing errors: the dose of ritonavir with renal failure should have read 100 mg, not 50 mg; and the suggested regimen for remdesivir should have been 3 days, not 5-10 days. The infographic has now been corrected.Publishers versio

Human Immunodeficiency Virus Reverse TranscriptaseA Bench-to-Bedside Success /

X, 361 p. 72 illus., 47 illus. in color.online re

Suppression of an intrinsic strand transfer activity of HIV-1 Tat protein by its second-exon sequences

AbstractThe Tat protein of human immunodeficiency virus type 1 (HIV-1) has been shown to restrict premature reverse transcription at late stages of virus infection and to thus ensure the integrity of the viral RNA genome for packaging. To gain further insights into the roles of Tat in HIV-1 reverse transcription, we have assessed its effects on the first-strand transfer during the synthesis of minus-strand DNA through use of a reconstituted cell-free system. The results demonstrated that a form of Tat, containing only the first exon (Tat72), was able to enhance the first-strand transfer as efficiently as did the viral nucleocapsid protein. Coincidentally, this form of Tat was unable to inhibit the production of minus-strand strong-stop DNA. Further studies with various mutated forms of Tat showed that its Cys-rich region, rather than the core and Arg-rich domains, was essential for this strand transfer activity. Moreover, this activity of Tat is largely independent of the TAR RNA structure. Although full-length Tat protein (Tat86) was also able to promote strand transfer, this activity was limited by a strong overall inhibition of reverse transcription because of the presence of the second Tat exon. Other nucleic-acid-binding proteins (e.g., single-strand DNA-binding protein) were employed as negative controls and were unable to promote strand transfer in these assays. We propose that Tat possesses nucleic acid chaperone activity and can promote the first-strand transfer during HIV-1 reverse transcription; however, these activities are restricted by the second Tat exon, and the roles of these Tat activities in viral replication remain to be elucidated

Structure-Activity Analysis of Vinylogous Urea Inhibitors of Human Immunodeficiency Virus-Encoded Ribonuclease H ▿

Vinylogous ureas 2-amino-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxamide and N-[3-(aminocarbonyl)-4,5-dimethyl-2-thienyl]-2-furancarboxamide (compounds 1 and 2, respectively) were recently identified to be modestly potent inhibitors of the RNase H activity of HIV-1 and HIV-2 reverse transcriptase (RT). Both compounds shared a 3-CONH2-substituted thiophene ring but were otherwise structurally unrelated, which prevented a precise definition of the pharmacophore. We have therefore examined a larger series of vinylogous ureas carrying amide, amine, and cycloalkane modifications of the thiophene ring of compound 1. While cycloheptane- and cyclohexane-substituted derivatives retained potency, cyclopentane and cyclooctane substitutions eliminated activity. In the presence of a cycloheptane ring, modifying the 2-NH2 or 3-CONH2 functions decreased the potency. With respect to compound 2, vinylogous ureas whose dimethylthiophene ring contained modifications of the 2-NH2 and 3-CONH2 functions were investigated. 2-NH2-modified analogs displayed potency equivalent to or enhanced over that of compound 2, the most active of which, compound 16, reflected intramolecular cyclization of the 2-NH2 and 3-CONH2 groups. Molecular modeling was used to define an inhibitor binding site in the p51 thumb subdomain, suggesting that an interaction with the catalytically conserved His539 of the p66 RNase H domain could underlie inhibition of RNase H activity. Collectively, our data indicate that multiple functional groups of vinylogous ureas contribute to their potencies as RNase H inhibitors. Finally, single-molecule spectroscopy indicates that vinylogous ureas have the property of altering the reverse transcriptase orientation on a model RNA-DNA hybrid mimicking initiation plus-strand DNA synthesis

The peroxisomal receptor Pex19p forms a helical mPTS recognition domain

The protein Pex19p functions as a receptor and chaperone of peroxisomal membrane proteins (PMPs). The crystal structure of the folded C-terminal part of the receptor reveals a globular domain that displays a bundle of three long helices in an antiparallel arrangement. Complementary functional experiments, using a range of truncated Pex19p constructs, show that the structured α-helical domain binds PMP-targeting signal (mPTS) sequences with about 10 μM affinity. Removal of a conserved N-terminal helical segment from the mPTS recognition domain impairs the ability for mPTS binding, indicating that it forms part of the mPTS-binding site. Pex19p variants with mutations in the same sequence segment abolish correct cargo import. Our data indicate a divided N-terminal and C-terminal structural arrangement in Pex19p, which is reminiscent of a similar division in the Pex5p receptor, to allow separation of cargo-targeting signal recognition and additional functions