This family consists of several bacterial histone H1-like Hc1 proteins. In Chlamydia, Hc1 is expressed in the late stages of the life cycle, concomitant with the reorganisation of chlamydial reticulate bodies into elementary bodies. This suggests that Hc1 protein plays a role in the condensation of chromatin during intracellular differentiation.
Jiyao W et al.(2023). "The conserved domain database in 2023.",