Abstract: Aspects of the present disclosure include methods for detecting a low abundance protein and methods for identifying a site of N-glycosylation on a protein. In practicing methods according to certain embodiments, a eukaryotic cell is contacted with an isotopic labeling composition and isotopically labeled N-glycosylated peptides obtained from the eukaryotic cell are assessed by liquid chromatography-tandem mass spectrometry. A predetermined isotopic pattern in the mass spectrum is identified and amino acid sequences of the peptides containing the predetermined isotopic pattern are determined. Systems for identifying a predetermined isotopic pattern in mass spectra and determining amino acid sequences of peptides containing the predetermined isotopic pattern are also described.

Abstract: Methods for producing isotopically-labelled peptides are provided. Aspects of the method include: contacting a sample including a metabolically tagged protein with a cleavable probe to produce a probe-protein conjugate; separating the probe-protein conjugate from the sample; digesting the probe-protein conjugate to produce a probe-peptide conjugate; and cleaving a cleavable linker to release an isotopically labelled peptide. The method may further include: identifying a predetermined isotopic pattern in a mass spectrum; determining an amino acid sequence of the isotopically labelled peptide; and identifying the site of protein glycosylation based on the determined amino acid sequence. Also provided are cleavable probes for practicing the subject methods, described by the Formula: A-L-(M-Z) where A is an affinity tag, L is a cleavable linker, M is an isotopic label and Z is a chemoselective tag capable of cross-linking a metabolically tagged protein.

Abstract: The present disclosure provides modified bacteria and modified peptidoglycan comprising modified D-amino acids; compositions comprising the modified bacteria or peptidoglycan; and methods of using the modified bacteria or peptidoglycan. The modified D-amino acids include a bioorthogonal functional group such as an azide, an alkyne or a norbornene group. Also provided are modified peptidoglycans conjugated to a molecule of interest via a linker.

Abstract: The present disclosure features a condensation reaction and a luciferin-unmasking reaction that can be carried out under physiological conditions. In general, the condensation reaction involves reacting a bicyclic reactant with an aminothiol derivative, generating a luciferin or luciferin derivative. A luciferin can provide detectable luminescence. A luciferin derivative can be unmasked to provide detectable luminescence in a luciferin-unmasking reaction. The present disclosure provides bicyclic reactants and aminothiol derivatives suitable for use in the condensation reaction. The condensation and luciferin-unmasking reactions find use in a variety of applications, which are also provided.

Abstract: The present disclosure features a condensation reaction and a luciferin-unmasking reaction that can be carried out under physiological conditions. In general, the condensation reaction involves reacting a bicyclic reactant with an aminothiol derivative, generating a luciferin or luciferin derivative. A luciferin can provide detectable luminescence. A luciferin derivative can be unmasked to provide detectable luminescence in a luciferin-unmasking reaction. The present disclosure provides bicyclic reactants and aminothiol derivatives suitable for use in the condensation reaction. The condensation and luciferin-unmasking reactions find use in a variety of applications, which are also provided.

Abstract: The present disclosure provides fluorogenic azide compounds. Also provided are methods of using the subject compounds for labelling a target biomolecule that includes an alkyne. In some embodiments, the method includes contacting the biomolecule with a fluorogenic azide compound, wherein the contacting results in covalent linkage of the compound with the alkyne moiety of the target biomolecule.

Abstract: Aspects of the present disclosure include methods for detecting a low abundance protein and methods for identifying a site of N-glycosylation on a protein. In practicing methods according to certain embodiments, a eukaryotic cell is contacted with an isotopic labeling composition and isotopically labeled N-glycosylated peptides obtained from the eukaryotic cell are assessed by liquid chromatography-tandem mass spectrometry. A predetermined isotopic pattern in the mass spectrum is identified and amino acid sequences of the peptides containing the predetermined isotopic pattern are determined. Systems for identifying a predetermined isotopic pattern in mass spectra and determining amino acid sequences of peptides containing the predetermined isotopic pattern are also described.

Abstract: The present disclosure provides modified bacteria and modified peptidoglycan comprising modified D-amino acids; compositions comprising the modified bacteria or peptidoglycan; and methods of using the modified bacteria or peptidoglycan. The modified D-amino acids include a bioorthogonal functional group such as an azide, an alkyne or a norbornene group. Also provided are modified peptidoglycans conjugated to a molecule of interest via a linker.

Abstract: Provided are modified cycloalkyne compounds; and methods of use of such compounds in modifying biomolecules. Embodiments include a cycloaddition reaction that can be carried out under physiological conditions. The cycloaddition reaction involves reacting a modified cycloalkyne with an azide moiety on a target biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provide for its application in vivo and in vitro.

Abstract: Provided are modified cycloalkyne compounds; and methods of use of such compounds in modifying biomolecules. Embodiments include a cycloaddition reaction that can be carried out under physiological conditions. The cycloaddition reaction involves reacting a modified cycloalkyne with an azide moiety on a target biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provide for its application in vivo and in vitro.

Abstract: The present disclosure provides compounds that detect reactive oxygen species in a living cell, in a multicellular organism, or in a cell-free sample. The compounds find use in a variety of applications, which are also provided. The present disclosure provides compositions comprising a subject compound.

Abstract: The present disclosure features a condensation reaction and a luciferin-unmasking reaction that can be carried out under physiological conditions. In general, the condensation reaction involves reacting a bicyclic reactant with an aminothiol derivative, generating a luciferin or luciferin derivative. A luciferin can provide detectable luminescence. A luciferin derivative can be unmasked to provide detectable luminescence in a luciferin-unmasking reaction. The present disclosure provides bicyclic reactants and aminothiol derivatives suitable for use in the condensation reaction. The condensation and luciferin-unmasking reactions find use in a variety of applications, which are also provided.

Abstract: A composite having a flexible hydrogel polymer formed by mixing an organic phase with an inorganic composition, the organic phase selected from the group consisting of a hydrogel monomer, a crosslinker, a radical initiator, and/or a solvent. A polymerization mixture is formed and polymerized into a desired shape and size.

Abstract: The present invention provides modified cycloalkyne compounds; and method of use of such compounds in modifying biomolecules. The present invention features a cycloaddition reaction that can be carried out under physiological conditions. In general, the invention involves reacting a modified cycloalkyne with an azide moiety on a target biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provide for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

Abstract: There is disclosed a method and device for the delivery of molecules into individual cells. A device for injecting a biological molecule into a target cell comprises a microscopic tip attached to a mechanical scanning device for positioning the tip relative to the target cell and for moving the tip into the target cell; a nanostructure, such as a carbon nanotube, fixed on an end of the microscopic tip; and a biological molecule attached to the nanotube by a cleavable electrostatic or chemical linker linking the biomolecule to the nanotube, said chemical linker having a chemical linkage which is cleaved in an intracellular environment. The biological molecule may be one or more of proteins, nucleic acids, small molecule drugs, and optical labels, and combinations thereof.

Abstract: The present disclosure provides a synthetic translation regulator, as well as gene expression cassettes and gene expression constructs comprising the synthetic translation regulator. The present disclosure further provides genetically modified bacterial host cells comprising a subject synthetic translation regulator; and methods of regulating gene expression in such host cells.

Abstract: Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated ?-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the ?-N-acetylgalactosamine groups on the nanostructure.

Abstract: Hydroxyapatite (HA)-binding peptides are selected using combinatorial phage library display. Pseudo-repetitive consensus amino acid sequences possessing periodic hydroxyl side chains in every two or three amino acid sequences are obtained. These sequences resemble the (Gly-Pro-Hyp)x repeat of human type I collagen, a major component of extracellular matrices of natural bone. A consistent presence of basic amino acid residues is also observed. The peptides are synthesized by the solid-phase synthetic method and then used for template-driven HA-mineralization. Microscopy reveal that the peptides template the growth of polycrystalline HA crystals ˜40 nm in size.

Abstract: The present invention provides modified cycloalkyne compounds; and method of use of such compounds in modifying biomolecules. The present invention features a cycloaddition reaction that can be carried out under physiological conditions. In general, the invention involves reacting a modified cycloalkyne with an azide moiety on a target biomolecule, generating a covalently modified biomolecule. The selectivity of the reaction and its compatibility with aqueous environments provide for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

Abstract: The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).