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Elissa M. Hobert

Bio: Elissa M. Hobert is an academic researcher from Yale University. The author has contributed to research in topics: Messenger RNA & Phosphorylation. The author has an hindex of 3, co-authored 3 publications receiving 217 citations.

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Journal ArticleDOI
TL;DR: RhoBo functions as a cell-permeable, turn-on fluorescent sensor for tetraserine motifs in recombinant proteins and current efforts to identify optimal serine-rich sequences for RhoBo suggest it to function effectively as a selective small-molecule label for appropriately tagged proteins either upon or within living cells.
Abstract: There is considerable interest in novel cell imaging tools that avoid the use of fluorescent proteins. One widely used class of such reagents are “pro-fluorescent” biarsenical dyes such as FlAsH, ReAsH, CrAsH, and Cy3As. Despite their utility, biarsenicals are plagued by high background labeling and cytotoxicity and are challenging to apply in oxidizing cellular locale. Here we demonstrate that [(3-oxospiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3′,6′-diyl)bis(iminomethylene-2,1-phenylene)]bis-(9CI), a rhodamine-derived bisboronic acid (RhoBo) described initially as a monosaccharide sensor, functions as a cell-permeable, turn-on fluorescent sensor for tetraserine motifs in recombinant proteins. RhoBo binds peptides or proteins containing Ser-Ser-Pro-Gly-Ser-Ser with affinities in the nanomolar concentration range and prefers this sequence to simple monosaccharides by >10 000-fold. RhoBo fails to form fluorescent complexes with constituents of the mammalian cell surface, as judged by epifluorescent, confocal...

159 citations

Journal ArticleDOI
TL;DR: Recent advances in visualizing protein associations and networks under increasingly native conditions include second generation protein complementation assays (PCAs), chemical and photo-crosslinking techniques, and proximity-induced ligation approaches.

40 citations

Journal ArticleDOI
TL;DR: This work reports that miniature-protein-based adaptor 3 uses templated catalysis to redirect the Src family kinase Hck to phosphorylate hDM2, a negative regulator of the p53 tumor suppressor and a poor Hck substrate.
Abstract: Signaling cascades are managed in time and space by interactions between and among proteins. These interactions are often aided by adaptor proteins, which guide enzyme–substrate pairs into proximity. Miniature proteins are a class of small, well-folded protein domains possessing engineered binding properties. Here we made use of two miniature proteins with complementary binding properties to create a synthetic adaptor protein that effectively redirects a ubiquitous signaling event: tyrosine phosphorylation. We report that miniature-protein-based adaptor 3 uses templated catalysis to redirect the Src family kinase Hck to phosphorylate hDM2, a negative regulator of the p53 tumor suppressor and a poor Hck substrate. Phosphorylation occurs with multiple turnover and at a single site targeted by c-Abl kinase in the cell.

25 citations

Journal ArticleDOI
TL;DR: In this article , a double mutant of T7 RNA polymerase (T7 RNAP) was engineered to produce substantially less immunostimulatory RNA during IVT compared with the wild-type T7RNAP.
Abstract: Abstract In vitro transcription (IVT) is a DNA-templated process for synthesizing long RNA transcripts, including messenger RNA (mRNA). For many research and commercial applications, IVT of mRNA is typically performed using bacteriophage T7 RNA polymerase (T7 RNAP) owing to its ability to produce full-length RNA transcripts with high fidelity; however, T7 RNAP can also produce immunostimulatory byproducts such as double-stranded RNA that can affect protein expression. Such byproducts require complex purification processes, using methods such as reversed-phase high-performance liquid chromatography, to yield safe and effective mRNA-based medicines. To minimize the need for downstream purification processes, we rationally and computationally engineered a double mutant of T7 RNAP that produces substantially less immunostimulatory RNA during IVT compared with wild-type T7 RNAP. The resulting mutant allows for a simplified production process with similar mRNA potency, lower immunostimulatory content and quicker manufacturing time compared with wild-type T7 RNAP. Herein, we describe the computational design and development of this improved T7 RNAP variant.

12 citations


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TL;DR: The bioorthogonal chemical reactions developed to date are described and how they can be used to study biomolecules.
Abstract: The study of biomolecules in their native environments is a challenging task because of the vast complexity of cellular systems. Technologies developed in the last few years for the selective modification of biological species in living systems have yielded new insights into cellular processes. Key to these new techniques are bioorthogonal chemical reactions, whose components must react rapidly and selectively with each other under physiological conditions in the presence of the plethora of functionality necessary to sustain life. Herein we describe the bioorthogonal chemical reactions developed to date and how they can be used to study biomolecules.

2,537 citations

Journal ArticleDOI
TL;DR: In this critical review the strategies for modification of Rhodamine dyes and a discussion on the variety of applications of these new derivatives as fluorescent probes are given.
Abstract: Rhodamine dyes are widely used as fluorescent probes owing to their high absorption coefficient and broad fluorescence in the visible region of electromagnetic spectrum, high fluorescence quantum yield and photostability. A great interest in the development of new synthetic procedures for preparation of Rhodamine derivatives has arisen in recent years because for most applications the probe must be covalently linked to another (bio)molecule or surface. In this critical review the strategies for modification of Rhodamine dyes and a discussion on the variety of applications of these new derivatives as fluorescent probes are given (108 references).

1,204 citations

Journal ArticleDOI
TL;DR: The robust reaction conditions and irreversible linkage of SpyTag shed light on spontaneous isopeptide bond formation and should provide a targetable lock in cells and a stable module for new protein architectures.
Abstract: Protein interactions with peptides generally have low thermodynamic and mechanical stability. Streptococcus pyogenes fibronectin-binding protein FbaB contains a domain with a spontaneous isopeptide bond between Lys and Asp. By splitting this domain and rational engineering of the fragments, we obtained a peptide (SpyTag) which formed an amide bond to its protein partner (SpyCatcher) in minutes. Reaction occurred in high yield simply upon mixing and amidst diverse conditions of pH, temperature, and buffer. SpyTag could be fused at either terminus or internally and reacted specifically at the mammalian cell surface. Peptide binding was not reversed by boiling or competing peptide. Single-molecule dynamic force spectroscopy showed that SpyTag did not separate from SpyCatcher until the force exceeded 1 nN, where covalent bonds snap. The robust reaction conditions and irreversible linkage of SpyTag shed light on spontaneous isopeptide bond formation and should provide a targetable lock in cells and a stable module for new protein architectures.

1,086 citations