Structure and Function of Archaeal SRP54 Protein Mutants Associated with Human Severe Congenital Neutropenia

SRP54, a key component of the signal recognition particle, is a highly conserved enzyme both structurally and functionally. The protein plays a vital role in cellular protein translocation by interacting with the translating ribosome and a membrane receptor, thereby aiding protein folding and trafficking. Recent studies have shown that mutations in the SRP54 gene cause severe neutropenia and are associated with an increased risk of pediatric leukemias. Here, we present high-resolution structures of clinically relevant SRP54 mutant proteins from the archaea Pyrococcus furiosus. This work complements existing structural and functional data on SRP54 and offers a high-resolution structural basis for clinically relevant congenital mutations. The structures of three mutants are presented along with the model wild type. Overall, the results provide a detailed understanding of how mutations affect SRP54 structure. Additionally, comparing our findings with available structures from higher eukaryotes offers new insights into the mechanisms of dysfunction.