Lanthanide tags for site-specific ligation to an unnatural amino acid and generation of pseudocontact shifts in proteins.
Bioconjug Chem
; 24(2): 260-8, 2013 Feb 20.
Article
em En
| MEDLINE
| ID: mdl-23294422
ABSTRACT
Pseudocontact shifts (PCS) from paramagnetic lanthanide ions present powerful long-range structural restraints for structural biology by NMR spectroscopy, but site-specific tagging of proteins with lanthanides remains a challenge, as most of the available lanthanide tags require proteins with single cysteine residues. We show that cyclen-based paramagnetic lanthanide tags can be attached to proteins in a site-specific manner by Cu(I)-catalyzed azide-alkyne cycloaddition to a genetically encoded p-azido-l-phenylalanine residue with a tether that proved sufficiently short and rigid for the observation of PCSs in several proteins. Despite the sterically demanding conditions associated with bulky tags and reactions close to the protein surface, ligation yields consistently above 50% and approaching 100% were obtained with the help of the Cu(I)-stabilizing ligand BTTAA. The yields were high independent of the presence of cysteine residues, thereby avoiding the need for cysteine mutations associated with conventional lanthanide-tagging strategies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenilalanina
/
Proteínas
/
Elementos da Série dos Lantanídeos
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article