Abstract: Substrates for ?-lactamase of the general formula I in which one of X and Y is a fluorescent donor moiety and the other is a quencher (which may or may not re-emit); R? is selected from the group consisting of H, lower (i.e., alkyl of 1 to about 5 carbon atoms) and (CH2)nOH, in which n is 0 or an integer from 1 to 5; R? is selected from the group consisting of H, physiologically acceptable metal and ammonium cations, —CHR2OCO(CH2)nCH3, —CHR2OCOC (CH3)3, acylthiomethyl, acyloxy-alpha-benzyl, delta-butyrolactonyl, methoxycarbonyloxymethyl, phenyl, methylsulphinylmethyl, beta-morpholinoethyl, dialkylaminoethyl, acyloxyalkyl, dialkylaminocarbonyloxymethyl and aliphatic, in which R2 is selected from the group consisting of H and lower alkyl; A is selected from the group consisting of S, O, SO, SO2 and CH2; and Z? and Z? are linkers for the fluorescent donor and quencher moieties.

Abstract: The present invention features biarsenical molecules. Target sequences that specifically react with the biarsenical molecules are also included. The present invention also features kits that include biarsenical molecules and target sequences. Tetraarsenical molecules are also featured in the invention.

Abstract: Fluorescent indicators including a binding protein moiety, a donor fluorescent protein moiety, and an acceptor fluorescent protein moiety are described. The binding protein moiety has an analyte-binding region which binds an analyte and causes the indicator to change conformation upon exposure to the analyte. The donor moiety and the acceptor moiety change position relative to each other when the analyte binds to the analyte-binding region. The donor moiety and the acceptor moiety exhibit fluorescence resonance energy transfer when the donor moiety is excited and the distance between the donor moiety and the acceptor moiety is small. The indicators can be used to measure analyte concentrations in samples, such as calcium ion concentrations in cells.

Abstract: A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. Cleavage of X allows separation of A from B, unmasking the normal ability of the basic amino acids in B to drag cargo C into cells near the cleavage event. X is cleaved extracellularly, preferably under physiological conditions. D-amino acids are preferred for the A and B portions, to minimize immunogenicity and nonspecific cleavage by background peptidases or proteases.

Abstract: The present invention provides a method for reducing undesirable light emission from a sample using at least one photon producing agent and at least one photon reducing agent (e.g. dye-based photon reducing agents). The present invention further provides a method for reducing undesirable light emission from a sample (e.g., a biochemical or cellular sample) with at least one photon producing agent and at least one collisional quencher. The present invention also provides a method for reducing undesirable light emission from a sample (e.g., a biochemical or cellular sample) with at least one photon producing agent and at least one quencher, such as an electronic quencher. The present invention also provides a system and method of screening test chemicals in fluorescent assays using photon reducing agents. The present invention also provides compositions, pharmaceutical compositions, and kits for practicing these methods.

Abstract: The present invention relates generally to fluorescent proteins and fluorescent protein variants, and more specifically to monomeric and dimeric forms of Anthozoan fluorescent proteins. In one aspect, the present invention provides variants of fluorescent proteins, where the variants have a reduced propensity to tetramerize, and form dimeric or monomeric structures. In a further aspect, the present invention provides variants of fluorescent proteins, the variants being characterized by more efficient maturation than corresponding fluorescent proteins from which they are derived. The invention also relates to methods of making and using such fluorescent proteins and fluorescent protein variants, including fluorescent protein monomers and dimers.

Abstract: The present invention relates to multi-well platforms, lids, caddies and any combination thereof. The multi-well platforms comprise a plurality of wells that can be of any shape and can be arranged in any ornamental pattern. The lid comprises an area corresponding to the well field. The caddy has a footprint approximately that of a standard 96-well microtiter plate. When the multi-well platform is engaged with the caddy, the wells of the well-field of the multi-well platform are preferably not obscured by the caddy when viewed from the bottom of the combination.

Abstract: The present invention features biarsenical molecules. Target sequences that specifically react with the biarsenical molecules are also included. The present invention also features kits that include biarsenical molecules and target sequences. Tetraarsenical molecules are also featured in the invention.

Abstract: This invention provides tandem fluorescent protein construct including a donor fluorescent protein moiety, an acceptor fluorescent protein moiety and a linker moiety that couples the donor and acceptor moieties. The donor and acceptor moieties exhibit fluorescence resonance energy transfer which is eliminated upon cleavage. The constructs are useful in enzymatic assays.

Abstract: The present invention relates generally to fluorescent proteins and fluorescent protein variants, and more specifically to monomeric and dimeric forms of Anthozoan fluorescent proteins. In one aspect, the present invention provides variants of fluorescent proteins, where the variants have a reduced propensity to tetramerize, and form dimeric or monomeric structures. In a further aspect, the present invention provides variants of fluorescent proteins, the variants being characterized by more efficient maturation than corresponding fluorescent proteins from which they are derived. The invention also relates to methods of making and using such fluorescent proteins and fluorescent protein variants, including fluorescent protein monomers and dimers.

Abstract: Methods and compositions are provided for determining the potential of a membrane. In one aspect, the method comprises: (a) introducing a first reagent comprising a hydrophobic fluorescent ion capable of redistributing from a first face of the membrane to a second face of the membrane in response to changes in the potential of the membrane, as described by the Nernst equation, (b) introducing a second reagent which labels the first face or the second face of the membrane, which second reagent comprises a chromophore capable of undergoing energy transfer by either (i) donating excited state energy to the fluorescent ion, or (ii) accepting excited state energy from the fluorescent ion, (c) exposing the membrane to radiation; (d) measuring energy transfer between the fluorescent ion and the second reagent, and (e) relating the energy transfer to the membrane potential. Energy transfer is typically measured by fluorescence resonance energy transfer.

Abstract: The present invention relates generally to fluorescent proteins and fluorescent protein variants, and more specifically to monomeric and dimeric forms of Anthozoan fluorescent proteins. In one aspect, the present invention provides variants of fluorescent proteins, where the variants have a reduced propensity to tetramerize, and form dimeric or monomeric structures. In a further aspect, the present invention provides variants of fluorescent proteins, the variants being characterized by more efficient maturation than corresponding fluorescent proteins from which they are derived. The invention also relates to methods of making and using such fluorescent proteins and fluorescent protein variants, including fluorescent protein monomers and dimers.

Abstract: The disclosure provides method and compositions for visualizing protein turnover. In particular, the disclosure provides methods and compositions useful for measuring the age of particular proteins or the dynamics of localized protein translation.

Abstract: The present invention relates to novel fluorescent protein variants of DsRed and eqFP578. Fluorescent protein variants having increased photostability and/or having reversible photoswitching behavior, as well as polynucleotides encoding such variants are provided herein. Methods of using these novel fluorescent protein variants and methods for constructing other fluorescent protein variants having increased photostability are also provided by the present invention.

Abstract: Engineered fluorescent proteins, nucleic acids encoding them and methods of use are provided.

Abstract: The present invention provides a method for reducing undesirable light emission from a sample using at least one photon producing agent and at least one photon reducing agent (e.g. dye-based photon reducing agents). The present invention further provides a method for reducing undesirable light emission from a sample (e.g. a biochemical or cellular sample) with at least one photon producing agent and at least one collisional quencher. The present invention also provides a method for reducing undesirable light emission from a sample (e.g., a biochemical or cellular sample) with at least one photon producing agent and at least one quencher, such as an electronic quencher. The present invention also provides a system and method of screening test chemicals in fluorescent assays using photon reducing agents. The present invention also provides compositions, pharmaceutical compositions, and kits for practicing these methods.

Abstract: The present invention relates to multi-well platforms, lids, caddies and any combination thereof. The multi-well platforms comprise a plurality of wells that can be of any shape and can be arranged in any ornamental pattern. The lid comprises an area corresponding to the well field. The caddy has a footprint approximately that of a standard 96-well microtiter plate. When the multi-well platform is engaged with the caddy, the wells of the well-field of the multi-well platform are preferably not obscured by the caddy when viewed from the bottom of the combination.

Abstract: The present invention features biarsenical molecules. Target sequences that specifically react with the biarsenical molecules are also included. The present invention also features kits that include biarsenical molecules and target sequences. Tetraarsenical molecules are also featured in the invention.

Abstract: The present invention relates to multi-well platforms, lids, caddies and any combination thereof. The multi-well platforms comprise a plurality of wells that can be of any shape and can be arranged in any ornamental pattern. The lid comprises an area corresponding to the well field. The caddy has a footprint approximately that of a standard 96-well microtiter plate. When the multi-well platform is engaged with the caddy, the wells of the well-field of the multi-well platform are preferably not obscured by the caddy when viewed from the bottom of the combination.

Abstract: Methods using somatic hypermutation (SHM) for producing polypeptide and nucleic acid variants, and nucleic acids encoding such polypeptide variants are disclosed. Such variants may have desired properties. Also disclosed are novel polypeptides, such as improved fluorescent proteins, produced by the novel methods, and nucleic acids, vectors, and host cells comprising such vectors.