The authors also demonstratedthe power for structural discovery by successfully mapping the interactiondomain between an uncharacterized protein YacL and RNA polymeraseusing the crosslinking data.41 A more focusedstudy by Sara Ayala Mariscal and colleagues used XL-MS to study thehuntingtin protein (HTT), whose expanded polyglutamine (polyQ) tractscause the neurodegenerative Huntington’s Disease through HTTaggregation. Here, HTT is linked to Huntington disease.