Method of immobilizing a protein or molecule via a mutant dehalogenase that is bound to an immobilized dehalogenase substrate and linked directly or indirectly to the protein or molecule

A method to immobilize a molecule of interest, comprising:

• a) providing a sample comprising one or more fusion proteins at least one of which comprises a mutant dehalogenase having at least 85% sequence identity to SEQ ID NO:82 and having substrate binding activity and a protein which is bound to the molecule of interest, and providing a solid support comprising one or more dehalogenase substrates, wherein the mutant dehalogenase comprises at least one amino acid substitution relative to SEQ ID NO:82, wherein the at least one amino acid substitution results in the mutant dehalogenase forming a bond with the substrate which has a half-life at least four times greater than that of the bond formed between SEQ ID NO:82 and the substrate, wherein the at least one amino acid substitution in the mutant dehalogenase is a substitution at an amino acid residue corresponding to residue 272 in a Rhodococcus dehalogenase having the amino acid sequence of SEQ ID NO:82;
• and
• b) contacting the sample and the solid support so as to form a complex having the molecule of interest immobilized on the solid support as a result of the bond formed between the mutant dehalogenase in one of the fusion proteins and one of the dehalogenase substrates on the solid substrate.