Dual-targeted labeling of proteins using cysteine and selenomethionine residues

Shenhui Lang; Donald E Spratt; J Guy Guillemette; Michael Palmer

doi:10.1016/j.ab.2005.04.036

Dual-targeted labeling of proteins using cysteine and selenomethionine residues

Anal Biochem. 2005 Jul 15;342(2):271-9. doi: 10.1016/j.ab.2005.04.036.

Authors

Shenhui Lang¹, Donald E Spratt, J Guy Guillemette, Michael Palmer

Affiliation

¹ Department of Chemistry, University of Waterloo, Waterloo, Ont., Canada N2L 3G1.

PMID: 15950913
DOI: 10.1016/j.ab.2005.04.036

Abstract

A new strategy for dual site-selective labeling of proteins that uses metabolically incorporated selenomethionine as a target for covalent modification by iodoacetamide derivatives, forming selenonium salts, is described. In the absence of free cysteine, labeling is specific and efficient. Dual-targeted labeling of a protein can be achieved with combinations of unique cysteine and methionine residues, if the cysteine is labeled first with a maleimide or another reagent that does not react with the selenomethionine. The method should be useful in biophysical applications such as fluorescence energy transfer.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacterial Proteins / chemistry
Calmodulin / chemistry
Calmodulin / genetics
Cysteine / chemistry*
Energy Transfer
Escherichia coli / metabolism
Fluorescence
Fluorescent Dyes / chemistry*
Hemolysin Proteins
Iodoacetamide / chemistry
Maleimides / chemistry
Mutagenesis, Site-Directed
Naphthalenesulfonates / chemistry
Proteins / chemistry*
Selenomethionine / chemistry*

Substances

AEDANS-calmodulin
Bacterial Proteins
CAMP protein, Streptococcus
Calmodulin
Fluorescent Dyes
Hemolysin Proteins
Maleimides
Naphthalenesulfonates
Proteins
maleimide
Selenomethionine
Cysteine
Iodoacetamide