title: P-azidoiodoacetanilide, a new short photocrosslinker that has greater cysteine specificity than p-azidophenacyl bromide and p-azidobromoacetanilide.
abstract: An important criterion for a protein modifying agent is its residue selectivity. We report the synthesis of a new photocrosslinking agent, p-azidoiodoacetanilide (AIA), which has a greater specificity to modify cysteine residues than the widely used p-azidophenacyl bromide (APB). Crosslinking of UmuD protein, which only has one cysteine, in the homodimer using APB or AIA resulted in 39% and 30% crosslinking, respectively; however, crosslinking of UmuD/C24A, a derivative with no cysteines, resulted in 16% crosslinked dimer using APB but only 2% using AIA. In addition, incorporation of [2-14C]APB into UmuD/C24A was 43% the amount of incorporation into wildtype UmuD, whereas incorporation of [2-14C]AIA into UmuD/C24A was only 13% the amount incorporated into wildtype UmuD. We also examined the cysteine specificity of p-azidobromoacetanilide (ABA) and found it to be less cysteine specific than AIA.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: M H
authors.initials: MH
authors.lastname: Lee
authors.forename: G C
authors.initials: GC
authors.lastname: Walker
mesh_terms: D000083:Acetanilides / Q000138:chemical synthesis / Q000737:chemistry*; D001386:Azides / Q000138:chemical synthesis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000138:chemical synthesis / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry*; D004259:DNA-Directed DNA Polymerase; D029968:Escherichia coli Proteins; D007202:Indicators and Reagents; D010777:Photochemistry
chemical_list: C097588:4-azidoiodoacetanilide; D000083:Acetanilides; D001386:Azides; D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D007202:Indicators and Reagents; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli; D003545:Cysteine; C011171:4-azidophenacyl bromide