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UTS, the Universal Tagging System for quantitative labeling of biomolecules

Stage: Prototype

Researchers at Los Alamos National Lab have developed a Universal Tagging System for 5 minute ultrasensitive protein quantification in cells or solutions. UTS has only two parts: uTag, a non-perturbing 15 amino acid tag genetically attached to any protein during expression; and uTagD, a small protein fragment that binds uTag to become fluorescent. uTagD is easily made on demand in a single cell or produced as a bulk lab reagent. Researchers designed UTS to track and optimize enzyme and antibody production, and to guide protein and pathway engineering.

Computational design, antibody development, and library screens will soon demand testing of up to millions of proteins to determine which are well expressed and folded. Existing approaches are expensive, work in only a few conditions, or use special equipment. UTS is low cost, works in all cell types and cell lysates, and it is compatible with microtiter plates, colony assays, and FACS. Millions of proteins can be screened in minutes. Proteins, enzymes, and antibodies are accurately tracked during production. uTag and the detector uTagD are highly engineered fragments of a fluorescent protein. Unlike other bulky tags UTS does not perturb the test system. uTagD binds uTag to become fluorescent, and each can be independently controlled in cells to quantify either total or soluble protein. Proteins can be quantified in lysates during production. The UTS system can be made by users cheaply and easily, eliminating costly exogenous reagents that accompany other tagging systems. Traditional approaches i.e. gel electrophoresis are low throughput. Other tags in the marketplace need special conditions, expensive reagents, specialized equipment, and don’t work with fluorescence based colony picking or flow sorting, while others are bulky, perturbing, and uses exogenous reagents. In contrast, UTS is non-perturbing, works in all cell types, uses no exogenous reagents, and quantifies proteins in cells or lysates. UTS is easily scalable from a few samples to millions. We have intellectual property on superfolder and two and three-part split green fluorescent proteins (GFPs). The portfolio is large. New fluorescent protein compositions, and hybrid technologies such as antibody mediated split protein assembly are in research and development. We are seeking a commercialization partner to either collaborate with us through a Cooperative Research and Development Agreement (CRADA) to further develop the technology for commercial purposes or license the technology directly from us. We are very interested in the continued research and development of UTS for: protein redesign, lab evolution, domain mapping, sensors, therapeutics, and binders.

Applications and Industries

Biofuels, biopolymers, therapeutic proteins, and enzymes are large markets. All depend on engineering and redesigning proteins and biopathways. Machine learning and in silico design are emerging as promising tools, spurring a need for high throughput expression and solubility screens. Current screening methods are cumbersome or restrictive, use expensive reagents, are non-quantitative, and lack sensitivity and throughput. UTS provides the solution for flexible, quantitative tools.


The two part assay only requires minutes for operation, avoids the need for expensive reagents, is easily produced at any scale, and provides high rates of protein screening. UTS is highly sensitive and provides linearity over orders of magnitude. The small size of the uTag enables pathway engineering applications.

    Quantify either total or soluble protein in intact cells in one step
    Quantify soluble lysates as well as unfolded insoluble fractions in vitro
    Orders-of-magnitude less expensive per assay than similar products in the marketplace
    Compatible with FACS
    uTagH, fully compatible with uTagD and UTS, can be used with IMAC resin for purification
    UTS components are inexpensive and can be made in-house
    Small size of uTag makes it friendly to CRISPR-based insertion and pathway engineering
    Easy to normalize cell-based activity assays, eliminating false positives
    Three colors of fluorescent tags are available