De novo design of modular and tunable protein biosensors.

Naturally occurring protein switches have been repurposed for the development of biosensors and reporters for cellular and clinical applications. However, the number of such switches is limited, and reengineering them is challenging. Here we show that a general class of protein-based biosensors can be created by inverting the flow of information through de novo designed protein switches in which the binding of a peptide key triggers biological outputs of interest.

design of modular and tunable allosteric biosensors.

Naturally occurring allosteric protein switches have been repurposed for developing novel biosensors and reporters for cellular and clinical applications , but the number of such switches is limited, and engineering them is often challenging as each is different. Here, we show that a very general class of allosteric protein-based biosensors can be created by inverting the flow of information through designed protein switches in which binding of a peptide key triggers biological outputs of interest . Using broadly applicable design principles, we allosterically couple binding of protein analytes of interest to the reconstitution of luciferase activity and a bioluminescent readout through the association of designed lock and key proteins.

Generation of a Human Monoclonal Antibody to Cross-Reactive Material 197 (CRM₁₉₇) and Development of a Sandwich ELISA for CRM₁₉₇ Conjugate Vaccines.

Cross-reactive material 197 (CRM₁₉₇) is a non-toxic mutant of diphtheria toxin containing a single amino acid substitution of glycine 52 with glutamic acid. CRM₁₉₇ has been used as a carrier protein for poorly immunogenic polysaccharide antigens to improve immune responses. In this study, to develop a sandwich ELISA that can detect CRM₁₉₇ and CRM₁₉₇ conjugate vaccines, we generated a human anti-CRM₁₉₇ monoclonal antibody (mAb) 3F9 using a phage-displayed human synthetic Fab library and produced mouse anti-CRM₁₉₇ polyclonal antibody.

Generation and Characterization of a Neutralizing Human Monoclonal Antibody to Hepatitis B Virus PreS1 from a Phage-Displayed Human Synthetic Fab Library.

The hepatitis B virus (HBV) envelope contains small (S), middle (M), and large (L) proteins. PreS1 of the L protein contains a receptor-binding motif crucial for HBV infection. This motif is highly conserved among 10 HBV genotypes (A-J), making it a potential target for the prevention of HBV infection.

Construction and Characterization of an Anti-Hepatitis B Virus preS1 Humanized Antibody that Binds to the Essential Receptor Binding Site.

Hepatitis B virus (HBV) is a major cause of liver cirrhosis and hepatocellular carcinoma. With recent identification of HBV receptor, inhibition of virus entry has become a promising concept in the development of new antiviral drugs. To date, 10 HBV genotypes (A-J) have been defined.

Purification, crystallization and X-ray crystallographic studies on a putative methyltransferase, YtqB, from Bacillus subtilis.

S-Adenosyl-L-methionine (SAM)-dependent methyltransferases (MTases) catalyze the transfer of a methyl group from a SAM cofactor to specific substrate molecules, including small chemicals, proteins, DNAs and RNAs, and are required for various cellular functions, such as regulation of gene expression and biosynthesis of metabolites. Bacillus subtilis YtqB is a putative SAM-dependent MTase whose biological function has not been characterized. To provide biochemical and structural insights into the role of YtqB in bacteria, the recombinant YtqB protein was overexpressed in the Escherichia coli expression system and purified by chromatographic methods.