Diamidocarbenes as versatile and reversible [2+1] cycloaddition reagents

We describe the synthesis of a variety of cyclopropanes and epoxides by combining a readily accessible and isolable N,N-2-diamidocarbene with a range of structurally and electronically diverse olefins and aldehydes, including electron-rich derivatives. Surprisingly, the cyclopropanation and epoxidation reactions were discovered to be rapid and thermally reversible at relatively low temperatures, two features often desired for applications that utilize dynamic covalent chemistry. In addition, a diamidocyclopropane derivative prepared via this method was hydrolysed successfully to form the corresponding linear carboxylic acid in a metal-and carbon monoxide-free hydrocarboxylation reaction. As such, diamidocarbenes are expected to find utility in the synthesis of cyclopropanes, epoxides and their derivatives, as well as in dynamic covalent chemistry applications.close424

Proteomic characterization of murid herpesvirus 4 extracellular virions.

Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV) and the Kaposi's sarcoma associated herpesvirus (KSHV) are highly prevalent pathogens that have been associated with several neoplastic diseases. As EBV and KSHV are host-range specific and replicate poorly in vitro, animal counterparts such as Murid herpesvirus-4 (MuHV-4) have been widely used as models. In this study, we used MuHV-4 in order to improve the knowledge about proteins that compose gammaherpesviruses virions. To this end, MuHV-4 extracellular virions were isolated and structural proteins were identified using liquid chromatography tandem mass spectrometry-based proteomic approaches. These analyses allowed the identification of 31 structural proteins encoded by the MuHV-4 genome which were classified as capsid (8), envelope (9), tegument (13) and unclassified (1) structural proteins. In addition, we estimated the relative abundance of the identified proteins in MuHV-4 virions by using exponentially modified protein abundance index analyses. In parallel, several host proteins were found in purified MuHV-4 virions including Annexin A2. Although Annexin A2 has previously been detected in different virions from various families, its role in the virion remains controversial. Interestingly, despite its relatively high abundance in virions, Annexin A2 was not essential for the growth of MuHV-4 in vitro. Altogether, these results extend previous work aimed at determining the composition of gammaherpesvirus virions and provide novel insights for understanding MuHV-4 biology