CSP41 protein has been shown to bind and cleave chloroplast RNA in vitro. Arabidopsis thaliana genome encodes two copies of this protein CSP41a (At3g63140) and CSP41b (At1g09340) , and they interacts each other physically. It has been suggested that CSP41a and CSP41b have a role in chloroplast ribosomal RNA metabolism, most likely acting in the final steps of 23S rRNA maturation.
