Covalent fragment screening and optimization identifies the chloroacetohydrazide scaffold as inhibitors for ubiquitin C-terminal hydrolase L1 von Imhoff, RD, Patel, R, Safdar, MH, Jones, HBL, Pinto-Fernandez, A, Vendrell, I, Chen, H, Muli, CS, Krabill, AD, Kessler, BM, Wendt, MK, Das, C, Flaherty, DP