Where does ligation collide?

In molecular biology, ligation is the enzyme-catalysed joining of two nucleic-acid ends, in which a DNA ligase forms a phosphodiester bond that seals a nick or splices a fragment into a vector, making it the step that actually closes a recombinant construct. Gellert's 1967 Formation of covalent circles of lambda DNA by E. coli extracts was among the reports that demonstrated this sealing activity by showing linear DNA converted to covalently closed circles. The referent is a bond-forming reaction between nucleotide chains, quantified by joining efficiency, and it is unrelated to tying off a vessel or chemically fusing peptides except through the shared meaning of joining.[1]

Unit

The efficiency with which two nucleic-acid ends are covalently joined

Recovery means

Not applicable

Measured by

Measured by the yield of joined or circularised product, often by gel electrophoresis or transformation of the ligated construct

In synthetic protein chemistry, ligation is the chemoselective joining of two unprotected peptide fragments into a single chain, and native chemical ligation does so by reacting a C-terminal thioester with an N-terminal cysteine to form a normal peptide bond at the junction. Dawson, Muir, Clark-Lewis, and Kent's 1994 Synthesis of proteins by native chemical ligation introduced the reaction that let chemists assemble full-length proteins from synthetic pieces in water. The referent is a bond-forming coupling of peptide segments, judged by the yield and purity of the fused product, and it is a distinct construct from sealing DNA or tying a vessel, joined only by the word's binding root.[2]

Unit

The yield and specificity of the peptide bond formed at the ligation junction

Recovery means

Not applicable

Measured by

Tracked by the yield of full-length product and the chemoselectivity of the junction, typically by chromatography and mass spectrometry