Biotin-c10-AppCH2ppA is an effective new chemical proteomics probe for diadenosine polyphosphate binding proteins

Here we report on the synthesis of a synthetic, stable biotin-c10-AppCH(2)ppA conjugate involving an unusual Cannizzaro reaction step. This conjugate is used to bind prospective AP(4)A binding proteins from Escherichia coli bacterial cell lyzates. Following binding, identities of these proteins are then determined smoothly by a process of magnetic bio-panning and electrospray mass spectrometry. Protein hits appear to be a definitive set of stress protein related targets. While this hit list may not be exclusive, and may vary with the nature of sampling conditions and organism status, nevertheless hits do appear to correspond with bona fide AP(4)A-binding proteins. Therefore these hits represent a sound basis on which to construct new hypotheses concerning the cellular importance of AP(4)A to bacterial cells and the potential biological significance of AP(4)A-protein binding interactions. (C) 2014 Published by Elsevier Ltd.