RNA transcripts receive a protective cap at their 5’ end to protect them from degradation. The most common is the 5’-m7 G cap, received by RNA polymerase II transcripts. However, if the RNA polymerase starts the transcription using a metabolite, like nicotinamide adenine dinucleotide (NAD), the RNA formed will have an alternative cap. The physiological roles and turnover of such NAD-capped RNAs are not well understood. It has been previously reported that human NUDT12 is a cytosolic enzyme capable of decapping m7 G-RNAs and NAD-capped RNAs, with a preference for the latter. The crystal structure of NUDT12 revealed that its homodimerization is essential for NUDT12 activity. It has also been reported that the cysteine protease bleomycin hydrolase (BLMH) is a direct interactor of NUDT12. Together, they form a 600 kDa dodecamer complex that is required for the localization of NUDT12 in cytoplasmic granules, distinct from P-bodies. My master thesis project aims to provide structural insights to the formation of this NUDT12-BLMH complex.