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Rapid Mapping of Protein Interactions Using Tag‐Transfer Photocrosslinkers
Author(s) -
Horne Jim E.,
Walko Martin,
Calabrese Antonio N.,
Levenstein Mark A.,
Brockwell David J.,
Kapur Nikil,
Wilson Andrew J.,
Radford Sheena E.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201809149
Subject(s) - diazirine , chemistry , reagent , combinatorial chemistry , residue (chemistry) , cysteine , alkylation , biophysics , stereochemistry , biochemistry , organic chemistry , enzyme , catalysis , biology
Analysing protein complexes by chemical crosslinking‐mass spectrometry (XL‐MS) is limited by the side‐chain reactivities and sizes of available crosslinkers, their slow reaction rates, and difficulties in crosslink enrichment, especially for rare, transient or dynamic complexes. Here we describe two new XL reagents that incorporate a methanethiosulfonate (MTS) group to label a reactive cysteine introduced into the bait protein, and a residue‐unbiased diazirine‐based photoactivatable XL group to trap its interacting partner(s). Reductive removal of the bait transfers a thiol‐containing fragment of the crosslinking reagent onto the target that can be alkylated and located by MS sequencing and exploited for enrichment, enabling the detection of low abundance crosslinks. Using these reagents and a bespoke UV LED irradiation platform, we show that maximum crosslinking yield is achieved within 10 seconds. The utility of this “tag and transfer” approach is demonstrated using a well‐defined peptide/protein regulatory interaction (BID 80‐102 /MCL‐1), and the dynamic interaction interface of a chaperone/substrate complex (Skp/OmpA).