A series of ankyrin repeat domains in Legionella provide a mechanism for histone recognition and methylation by RomA.

March 1, 2024

The Legionella bacterium are widely found in nature and interact with protozoa for replication. While generally harmless to humans, the inhalation of Legionella-contaminated aerosols can cause a form of pneumonia called Legionnaires' disease. Understanding the life cycle of Legionella has impacts on the ability of the bacterium to target human cells

By solving the structure of RomA bound to the N-terminal tail of histone H3, Rolando et al. were able to determine the interactions required for histone binding and target of methylation during host-cell infection. Methylation was only observed when interactions between the ankyrin domains and N-terminal peptide of H3 was preserved, providing insight into the ankyrin domain repeats throughout the Legionella genome. The results of this work provide a means to study the evolutionary role of gene transfer in Legionella.

PDB: 8SWI

Article: Rolando, Monica, et al. "The SET and ankyrin domains of the secreted Legionella pneumophila histone methyltransferase work together to modify host chromatin." Mbio 14.5 (2023): e01655-23.