Abstract: This disclosure provides the construction, expression, and selection of the mutated genes that encode novel Trp cage polypeptides with desirable binding properties, as well as the novel Trp cage polypeptides themselves. The substances or targets bound by these novel Trp cage polypeptides may be but need not be proteins or polypeptides. Targets may include other biological or synthetic macromolecules as well as other organic and inorganic substances. Further, targets may also include a single or multiple cell or tissue types. The present invention achieves genetic variants of Trp cage-encoding nucleic acids through controlled random mutagenesis of the nucleic acids yielding a mixture of Trp cage polypeptides that are capable of binding targets.

Abstract: The present disclosure relates to the construction, expression, and selection of genes that encode novel Trp cage polypeptides with desirable cell and/or tissue binding properties, as well as the novel Trp cage polypeptides themselves. A polypeptide of this disclosure may contain all or part of amino acid sequence AAADX1YX2QWLX3X4X5GPX6SGRPPPX7 (SEQ ID NO: 4), wherein Xn represents an amino acid found in position n, the polypeptide comprising a tryptophan cage (Trp cage).

Abstract: The use of antagonists to JAM-1 Claudin-4 and occludin to open tight junctions. The antagonists include, by way of example antibodies and antibody fragments that bind to the proteins and small interfering nucleic acids that downregulate the mRNA encoding the proteins.