Engineering of the hepatitis C virus helicase for enhanced seroreactivity.

Hepatitis C Virus c33, a recombinant protein comprising residues 1192-1457 of NS3 helicase, has been a mainstay of HCV serology for decades. With seven unpaired cysteines, seroreactivity of E. coli expressed c33 is dependant on reductants.

Cysteinylation of a monoclonal antibody leads to its inactivation.

Post-translational modifications can have a signification effect on antibody stability. A comprehensive approach is often required to best understand the underlying reasons the modification affects the antibody's potency or aggregation state. Monoclonal antibody 001 displayed significant variation in terms of potency, as defined by surface plasmon resonance testing (Biacore), from lot to lot independent of any observable aggregation or degradation, suggesting that a post-translational modification could be driving this variability.

Non-catalytic function for ATR in the checkpoint response.

The ATR family of checkpoint kinases is essential for an appropriate response to genomic insults in eukaryotes. Included in this family are Mei-41 in Drosophila, Mec1 inS. cerevisiae, Rad3 in S.

Xenopus Cds1 is regulated by DNA-dependent protein kinase and ATR during the cell cycle checkpoint response to double-stranded DNA ends.

The checkpoint kinase Cds1 (Chk2) plays a key role in cell cycle checkpoint responses with functions in cell cycle arrest, DNA repair, and induction of apoptosis. Proper regulation of Cds1 is essential for appropriate cellular responses to checkpoint-inducing insults. While the kinase ATM has been shown to be important in the regulation of human Cds1 (hCds1), here we report that the kinases ATR and DNA-dependent protein kinase (DNA-PK) play more significant roles in the regulation of Xenopus Cds1 (XCds1).