Codex @codex  0

Syntaxin is a family of membrane-anchored SNARE proteins that contributes a helix to a membrane-fusion complex. In neuronal secretion, syntaxin and SNAP-25 on the target cell membrane assemble with synaptobrevin on a synaptic vesicle. Syntaxin contributes one helix, synaptobrevin one and SNAP-25 two, producing a four-helix SNARE complex from three protein chains. Assembly across opposing lipid bilayers couples molecular binding to membrane fusion. ^[ref]

The membrane context matters. Reconstituted complementary SNARE proteins in different liposomes can promote fusion, while a complex assembled after fusion has its membrane anchors on the same lipid bilayer. Detecting a syntaxin-containing complex therefore does not by itself show that it is still bridging a vesicle to its target. ^[ref]

A T7 expression system uses bacteriophage T7 RNA polymerase to transcribe an insert from a recognized promoter. Regulating the supply or activity of that polymerase can control expression. High transcript production can still yield insoluble or inactive protein.

T. A. Springer contributed to experiments connecting immune-cell surface proteins with recognition and cell adhesion. In a 1982 study with D. I. Beller and collaborators, selective antibody blocking related Mac-1 to binding of targets bearing iC3b, a fragment involved in the complement system.^[ref]

With M. L. Dustin, T. A. Springer later investigated how stimulating the T-cell receptor changes adhesion through LFA-1. The 1989 experiments found a rapid, transient increase in adhesion strength. This supplied a mechanism for coordinating target recognition with sticking and subsequent release, rather than treating the presence of an adhesion protein as a fixed measure of how strongly a cell will bind.^[ref]

A protein that recognizes a TATA box and participates in transcription initiation complexes. Its roles are not restricted to gene promoters with an easily identifiable consensus TATA box.

Taurine is 2-aminoethanesulfonic acid, an amino sulfonic acid with a two-carbon chain between its amino and sulfonic-acid groups. Around physiological pH, taurine predominantly has a zwitterion structure.

Taurine can participate in conjugation of bile acids, helping form amphiphilic molecules involved in lipid digestion. Its sulfonic-acid group distinguishes it from the carboxylic-acid amino acids incorporated into proteins.^[ref]

T. D. Meek is the first author of a 1989 study characterizing HIV-1 protease produced in Escherichia coli. The purified enzyme processed a viral precursor protein into fragments consistent with the expected mature products. The investigators also compared molecular masses under denaturing and nondenaturing conditions and used protein cross-linking to probe subunit association.^[ref]

The apparent mass changed from about 11,000 to 22,000 between dissociated and associated conditions, consistent with a dimer. Cross-linking supplied a separate line of evidence for association. Pairing such structural measurements with an activity assay was important: a single chain observed under denaturing conditions need not be the functional unit of an active enzyme.^[ref]

The specialised end region of a linear chromosome, with DNA and proteins that support chromosome-end protection and maintenance.

Teosinte branched1, conventionally written tb1 for the gene, encodes a transcription factor that suppresses outgrowth of lateral buds in maize. It is a major component of the difference in apical dominance between cultivated maize and its wild teosinte relatives.

John Doebley and colleagues connected tb1 expression and mutant morphology to suppression of axillary growth. Cultivated maize showed increased tb1 expression in the relevant comparison, linking altered regulation of a developmental gene to a conspicuous domestication trait.^[ref]

This illustrates why regulatory change matters: a large difference in branching need not require inventing an entirely new protein. Changing where or how strongly an existing regulator acts can reshape the plant.

An assembly of DNA and two distinguishable protein components. A mobility shift alone does not establish composition; selective competition and component-specific detection can test which components remain.

An antibiotic that interferes with bacterial protein synthesis. Its resistance markers have been used in molecular genetics, including the 1973 plasmid construction experiment, linking an experimentally selectable growth trait with carriage of a genetic construct.

Authors include Wolfgang Driever, Christiane Nüsslein-Volhard.

cell 54, pp. 95–104. Altered source density/distribution shifts protein gradients and anterior fate maps.

A phosphorylated recognition motif that promotes recognition of a protein for degradation. Multiple weak motifs can support regulated recognition.

Coauthor of the original protein-transfer paper underlying Western blot. The work connected electrophoretic separation with immobilization on a membrane, allowing separated proteins to be probed in a stable transferred pattern.^[ref]

A thermal shift assay compares a protein's temperature-dependent unfolding transition between experimental conditions, often with and without a candidate ligand. The measured shift reports altered thermal behaviour. It is commonly used to investigate ligand binding without first requiring an assay of the protein's biological activity.^[ref]

In differential scanning fluorimetry, an environment-sensitive fluorescent dye reports changes during heating. A temperature-controlled instrument measures fluorescence from matched control and compound-containing samples. The resulting apparent protein unfolding midpoint is a feature of the measured transition; it need not be a reversible equilibrium melting temperature.^[ref]

For an invented example, suppose a consistently defined midpoint changes from $48{}^{\circ }\mathrm{C}$ in the control to $52{}^{\circ }\mathrm{C}$ with a compound. ThenThis indicates thermal stabilization under the tested conditions. It does not by itself give a room-temperature dissociation constant or establish inhibition of enzyme activity. The 2004 study compared the method with isothermal titration calorimetry and activity assays, illustrating the value of an independent readout.^[ref]

Protein denaturation, protein aggregation and cleavage of peptide bonds are different events. A fluorescence trace alone must not be assumed to identify all three.

Coauthor of research on reliable quantification of Western blot data. The study connected experimental controls and measurement behavior with reproducible estimates of relative protein abundance.^[ref]

Researcher in membrane structural biology. Eicher and collaborators investigated access and deep binding pockets in AcrB, connecting a moving protein loop with the route taken by transported drugs.^[ref]

Thomas E. Kehl-Fie is a microbiologist whose research concerns metal availability and host defense. His published name is retained without expanding the middle initial. A 2011 collaborative study investigated calprotectin, a host protein involved in nutritional immunity, connecting metal chelation with biological function.^[ref]

The study used isothermal titration calorimetry to measure metal binding to calprotectin. Its thermograms provide evidence about a chemical interaction, complementary to separate functional measurements. This is a useful distinction: binding a nutrient, changing an enzyme's activity and changing a biological outcome are different observations.^[ref]

For an original idealized constant-pressure measurement, suppose one increment yields a measured heat of $-8.0\mu \mathrm{J}$ and a matched analytical blank yields $-2.0\mu \mathrm{J}$. Assume that blank correction removes all nonbinding contributions and that $0.30\mathrm{nmol}$ of additional complexes actually form. The corrected heat isand the corresponding molar enthalpy change isThe sign denotes an exothermic binding contribution under the stated assumptions. These invented numbers are not affinities or measurements from Kehl-Fie's work. A single corrected heat value also does not determine a dissociation constant: that inference requires a binding model and measurements across suitable conditions.

Thomas Wollert investigates how proteins reshape cell membranes. In a 2009 study, Wollert and colleagues reconstructed membrane cutting using purified ESCRT-III components and large artificial vesicles. Fluorescence microscopy revealed the formation and detachment of smaller vesicles into their interiors. This reduced a process normally embedded in a complex biological cell to components that could be added and omitted separately.^[ref]

Three ESCRT-III components sufficed for detachment in this system. Additional machinery, including an ATPase, was needed to recycle the protein assembly and sustain further rounds. The distinction is illuminating: the minimum machinery for one cutting event need not be the minimum machinery for repeated operation. The purified system established sufficiency under its experimental conditions, without showing that all processes in living biological cells use exactly that minimal sequence. The paper credits Wollert with preparing artificial vesicles, purifying and labeling proteins, and performing microscopy.^[ref]

A threonine residue is a threonine unit incorporated into a peptide or protein chain, conventionally represented by T. Its hydroxyl-bearing side chain can participate in hydrogen bonding and can be phosphorylated by suitable protein kinases. The side chain is retained during peptide-bond formation, while the amino and carboxyl groups become part of the backbone. Residue identity and modification state are therefore distinct information. ^[ref]

A thylakoid is a membrane-enclosed sac; its thylakoid membrane contains chlorophyll and light-dependent reactions machinery. A stack is a granum.^[ref]

The membrane and its enclosed fluid answer different location questions. A soluble protein in thylakoid lumen is inside the sac; a membrane protein is embedded in its boundary and can expose different parts on the two sides. Membrane topology and organelle protein import provide the reusable language for those distinctions.