Lglycine (Invitrogen; Cat#: C10186). Cells were fixed in chilled methanol, washed

Lglycine (Invitrogen; Cat#: C10186). Cells had been fixed in chilled methanol, washed with PBS, and incubated in Click-iT reaction cocktail (Invitrogen; Cat#: C10269) containing Alexa Fluor 555 Azide (Invitrogen; Cat#:…