GROUP-SPECIFIC ANTIBODIES AGAINST THE PUTATIVE AMP-BINDING DOMAIN SIGNATURE SGTTGXPKG IN PEPTIDE SYNTHETASES AND RELATED ENZYMES

The superfamily of adenylate forming enzymes including peptide synthet ases, acyl-CoA synthetases and insect luciferases is readily identifie d by the signature sequence SGTTGXPKG. This sequence including an inva riant lysyl residue is located in a disordered loop region and was pre dicted to be of significant antigenicity. Antibodies were generated em ploying YTSGTTGRPKGC attached to bovine serum albumin and have been su ccessfully used to identify respective enzymes and adenylate forming d omains in multienzyme systems. These include the delta-(L-alpha-aminoa dipyl)-L-cysteinyl-D-valine synthetases of Aspergillus nidulans and Ac remonium chrysogenum, gramicidin S synthetase 1 and tyrocidine synthet ase 1 from Bacillus brevis, acetyl-CoA synthetase from Alcaligenes eut rophus and a putative peptide synthetase from Metarhizium anisopliae. Weaker or no reactions are observed when the amino acid in position X in the protein is non-basic or hydrophobic, which is respectively the case for gramicidin S synthetase 1 and luciferase.