A novel druggable interprotomer pocket in the capsid of rhino- and enteroviruses

Rhino- and enteroviruses are important human pathogens, against which no antivirals are available. The best-studied inhibitors are "capsid binders" that fit in a hydrophobic pocket of the viral capsid. Employing a new class of entero-/rhinovirus inhibitors and by means of cryo-electron microscopy (EM), followed by resistance selection and reverse genetics, we discovered a hitherto unknown druggable pocket that is formed by viral proteins VP1 and VP3 and that is conserved across entero-/rhinovirus species. We propose that these inhibitors stabilize a key region of the virion, thereby preventing the conformational expansion needed for viral RNA release. A medicinal chemistry effort resulted in the identification of analogues targeting this pocket with broad-spectrum activity against Coxsackieviruses B (CVBs) and compounds with activity against enteroviruses (EV) of groups C and D, and even rhinoviruses (RV). Our findings provide novel insights in the biology of the entry of entero-/rhinoviruses and open new avenues for the design of broad-spectrum antivirals against these pathogens.

Crystal structures of N-(4-chloro-phen-yl)-2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]acetamide and N-(3-chloro-phen-yl)-2-[(4,6-di-amino-pyrimidin-2-yl)sulfan-yl]acetamide

The title compounds, C12H12ClN5OS, (I), and C12H12ClN5OS, (II), are 2-[(di-amino-pyrimidin-2-yl)sulfan-yl]acetamides. Compound (II), crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In each of the mol-ecules, in both (I) and (II), an intra-molecular N-H⋯N hydrogen bond forms an S(7) ring motif. The pyrimidine ring is inclined to the benzene ring by 42.25 (14)° in (I), and by 59.70 (16) and 62.18 (15)° in mol-ecules A and B, respectively, of compound (II). In the crystal of (I), mol-ecules are linked by pairs of N-H⋯N hydrogen bonds, forming inversion dimers with an R22(8) ring motif. The dimers are linked via bifurcated N-H⋯O and C-H⋯O hydrogen bonds, forming corrugated layers parallel to the ac plane. In the crystal of (II), the A mol-ecules are linked through N-H⋯O and N-H⋯Cl hydrogen bonds, forming layers parallel to (100). The B mol-ecules are also linked by N-H⋯O and N-H⋯Cl hydrogen bonds, also forming layers parallel to (100). The parallel layers of A and B mol-ecules are linked via N-H⋯N hydrogen bonds, forming a three-dimensional structure.

Crystal structures of 2-[(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(naphthalen-1-yl)acetamide and 2-[(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluorophenyl)acetamide

The two title compounds are (di­amino­pyrimidin-2-yl)thio­acetamide derivatives. In the first structure, the pyrimidine ring is inclined to the naphthalene ring system by 55.5 (1)°, while in the second, the pyrimidine ring is inclined to the benzene ring by 58.93 (8)°. In the crystals of both compounds, mol­ecules are linked by pairs of N—H⋯N hydrogen bonds, forming inversion dimers with (8) ring motifs.

The title compounds, C₁₆H₁₅N₅OS, (I), and C₁₂H₁₂FN₅OS, (II), are [(di­amino­pyrimidine)­sulfan­yl]acetamide derivatives. In (I), the pyrimidine ring is inclined to the naphthalene ring system by 55.5 (1)°, while in (II), the pyrimidine ring is inclined to the benzene ring by 58.93 (8)°. In (II), there is an intra­molecular N—H⋯N hydrogen bond and a short C—H⋯O contact. In the crystals of (I) and (II), mol­ecules are linked by pairs of N—H⋯N hydrogen bonds, forming inversion dimers with R₂²(8) ring motifs. In the crystal of (I), the dimers are linked by bifurcated N—H⋯(O,O) and C—H⋯O hydrogen bonds, forming layers parallel to (100). In the crystal of (II), the dimers are linked by N—H⋯O hydrogen bonds, also forming layers parallel to (100). The layers are linked by C—H⋯F hydrogen bonds, forming a three-dimensional architecture.

2-[(4,6-Diaminopyrimidin-2-yl)sulfanyl]-N-(2-methylphenyl)acetamide

In the title compound, C₁₃H₁₅NOS, the plane of the pyrimidine ring makes a dihedral angle of 54.73 (9)° with that of the o-tolyl ring. The mol­ecule adopts an extended conformation, which is evident from the C—C(=O)—N—C_ar (ar = aromatic) torsion angle of 178.42 (15)°. In the crystal, mol­ecules are linked via pairs of N—H⋯N hydrogen bonds, forming inversion dimers with an R²₂(8) ring motif. The dimers are linked by N—H⋯O and C—H⋯O hydrogen bonds, with the O atom accepting three such interactions, forming sheets parallel to (100).

Experience establishing tuberculosis laboratory capacity in a developing country setting

OBJECTIVE

To describe the experience of strengthening laboratory diagnosis of tuberculosis (TB) in a resource-limited country with high TB-HIV (human immunodeficiency virus) and multidrug-resistant TB (MDR-TB) prevalence.

METHODS

In the Kingdom of Lesotho, which is confronted with high levels of TB, MDR-TB and HIV prevalence, between 2006 and 2008 a coalition of the Foundation for Innovative New Diagnostics, Partners In Health and the World Health Organization renovated the National TB Reference Laboratory and reinforced microscopy services, streamlined conventional culture and drug susceptibility testing (DST) and introduced modern TB diagnostic methods.

FINDINGS

It was feasible to establish a biosafety level three facility for solid culture and DST and an external quality assessment programme for smear microscopy within 4 months, all in 2007. Liquid culture and DST were introduced a month later. Preliminary results were comparable to those found in laboratories in industrialised countries. A year later, line-probe assay for the rapid detection of MDR-TB was introduced.

DISCUSSION

Through strong political commitment and collaboration, it is possible to rapidly establish quality assured TB diagnostic capacity, including current methods, in a resource-limited setting. Case detection and management for TB and MDR-TB have been greatly enhanced. From a low baseline, TB culture throughput in the laboratory increased ten-fold and has been sustained. This experience has served as a catalyst to translate policy into practice with new diagnostic technologies. It supports global policy setting to enhance and modernise laboratory work in developing countries.