Although traditional IgG antibodies are often used for immunoprecipitation and protein interaction analysis, GFP-binding protein (GBP, ChromoTek gt-250) and other ChromoTek VHHs (https://www.chromotek.com/about-us/the-alpaca-antibody-advantage/) easily outcompete those under challenging conditions such as elevated temperatures, varying pH or high denaturant concentrations. In fact, GBP tightly binds GFP-fusion proteins even in 8 M urea at 51 °C, which sets a new limit in protein complex stability, virtually unrivalled by any other capture molecule protein tag pair.