LC-MS/MS analysis
HERC5-Flag, along with WT or MUT OspC1, overexpressed in 293T cells was immunoprecipitated with anti-Flag M1 agarose affinity gel (Sigma-Aldrich, A4596-5ml) 24 h after transfection and then subjected to SDS-PAGE separation and Coomassie Blue staining. Target HERC5-Flag bands were taken for in-gel digestion with trypsin according to a standard protocol, followed by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis on Thermo ScientificTM Orbitrap FusionTM coupled with UltiMate3000. The MS/MS spectra of modified peptides were acquired by searching the raw data with Mascot (version 2.3.02, Matrix Science).