Provided herein are libraries of scaffolds derived from riboswitches and small ribozymes and their methods of use. The scaffolds of the invention yield aptamers that are easily identified and characterized by virtue of the structural scaffold. The nature of the scaffold predisposes these RNAs for coupling to readout domains to engineer biosensors that function in vitro and in vivo. Biosensors, synthetic RNA agents and synthetic DNA agents, and their methods of use, are also provided.

Disclosed are compositions and method related to variants of SPINK2 that bind to targets other than an endogenous target of SPINK2. In one embodiment, a peptide is provided that comprises the amino acid sequence SEQ ID NO: 1. In further embodiments, an amino acid sequences encoded by nucleotide positions 4 to 42 and/or nucleotide positions 94 to 189 in the nucleotide sequence of SEQ ID NO: 14 flank the amino terminus and the carboxyl terminus, respectively, of the amino acid sequence. In another embodiment, a peptide is provided that comprises an amino acid sequence derived from the amino acid sequence of SEQ ID NO: 1 in which a conservative substitution, deletion, addition and/or insertion of 1 to 5 (inclusive) amino acids has occurred at amino acids other than the 1st Xaa to the 12th Xaa counting from the amino terminus.

The invention provides a protein scaffold and methods of preparing, screening, engineering and using the protein scaffold.

Fibronectin type III (.sup.10Fn3) binding domains having novel designs that are associated with reduced immunogenicity are provided. The application describes alternative .sup.10Fn3 binding domains in which certain immunogenic regions are not modified when producing a binder in order to maintain recognition as a self antigen by the host organism. The application also describes .sup.10Fn3 binding domains in which HLA anchor regions have been destroyed thereby reducing the immunogenic contribution of the adjoining region. Also provided are .sup.10Fn3 domains having novel combinations of modified regions that can bind to a desired target with high affinity.

Disclosed herein are expression vectors which display a passenger polypeptide on the outer surface of a biological entity. As disclosed herein the displayed passenger polypeptide is capable of interacting or binding with a given ligand. Also disclosed are methods of making and using the expression vectors. N/C terminal fusion expression vectors and methods of making and using are also disclosed.

Polypeptide are disclosed that comprise an amino acid sequence at least 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identical to the amino acid sequence selected from the group consisting of SEQ ID NO:1-1615, not including any functional domains added fused to the protein (whether N-terminal, C-terminal, or internal), and wherein the 1, 2, 3, 4, or 5 N-terminal and/or C-terminal amino acid residues may be present or absent when considering the percent identity.

This invention relates to modular proteins that interact with one or more target molecules. The chimeric proteins comprise two or more repeat domains, such as tetratricopeptide repeat domains; inter-repeat loops linking the repeat domains; and one or more peptide ligands. Each peptide ligand is located in an inter-repeat loop or at the N or C terminus of the chimeric protein. The peptide ligands may include heterologous peptidyl binding motifs, such as short linear motifs (SLiMs). Chimeric proteins with various configurations and methods for their production and use are provided.

Fibronectin type III (.sup.10Fn3) binding domains having novel designs that are associated with reduced immunogenicity are provided. The application describes alternative .sup.10Fn3 binding domains in which certain immunogenic regions are not modified when producing a binder in order to maintain recognition as a self antigen by the host organism. The application also describes .sup.10Fn3 binding domains in which HLA anchor regions have been destroyed thereby reducing the immunogenic contribution of the adjoining region. Also provided are .sup.10Fn3 domains having novel combinations of modified regions that can bind to a desired target with high affinity.

Provided herein are methods and compositions relating to G protein-coupled receptor (GPCR) libraries having nucleic acids encoding for a scaffold comprising a GPCR binding domain. Libraries described herein include variegated libraries comprising nucleic acids each encoding for a predetermined variant of at least one predetermined reference nucleic acid sequence. Further described herein are protein libraries generated when the nucleic acid libraries are translated. Further described herein are cell libraries expressing variegated nucleic acid libraries described herein.

Provided herein are methods and compositions relating to G protein-coupled receptor (GPCR) libraries having nucleic acids encoding for a scaffold comprising a GPCR binding domain. Libraries described herein include variegated libraries comprising nucleic acids each encoding for a predetermined variant of at least one predetermined reference nucleic acid sequence. Further described herein are protein libraries generated when the nucleic acid libraries are translated. Further described herein are cell libraries expressing variegated nucleic acid libraries described herein.