Role for ADP ribosylation factor 1 in the regulation of hepatitis C virus replication.

We hypothesized that ADP-ribosylation factor 1 (Arf1) plays an important role in the biogenesis and maintenance of infectious hepatitis C virus (HCV). Huh7.5 cells, in which HCV replicates and produces infectious viral particles, were exposed to brefeldin A or golgicide A, pharmacological inhibitors of Arf1 activation.

Hepatitis C virus core protein associates with detergent-resistant membranes distinct from classical plasma membrane rafts.

A subpopulation of hepatitis C virus (HCV) core protein in cells harboring full-length HCV replicons is biochemically associated with detergent-resistant membranes (DRMs) in a manner similar to that of markers of classical lipid rafts. Core protein does not, however, colocalize in immunofluorescence studies with classical plasma membrane raft markers, such as caveolin-1 and the B subunit of cholera toxin, suggesting that core protein is bound to cytoplasmic raft microdomains distinct from caveolin-based rafts. Furthermore, while both the structural core protein and the nonstructural protein NS5A associate with membranes, they do not colocalize in the DRMs.

Structure-based rational design of streptavidin mutants with pseudo-catalytic activity.

Introduction of enzymatic activity into proteins or other types of polymers by rational design is a major objective in the life sciences. To date, relatively low levels of enzymatic activity could be introduced into antibodies by using transition-state analogues of haptens. In the present study, we identify the structural elements that contribute to the observed hydrolytic activity in egg white avidin, which promote the cleavage of active biotin esters (notably biotinyl p-nitrophenyl ester).