An evolutionarily conserved tryptophan cage promotes folding of the extended RNA recognition motif in the hnRNPR-like protein family.

ABSTRACT: The heterogeneous nuclear ribonucleoprotein (hnRNP) R-like family is a class of RNA binding proteins in the hnRNP superfamily with diverse functions in RNA processing. Here, we present the 1.90 Å X-ray crystal structure and solution NMR studies of the first RNA recognition motif (RRM) of human hnRNPR. We find that this domain adopts an extended RRM (eRRM1) featuring a canonical RRM with a structured N-terminal extension (N_ext) motif that docks against the RRM and extends the β-sheet surface. The adjoining loop is structured and forms a tryptophan cage motif to position the N_ext motif for docking to the RRM. Combining mutagenesis, solution NMR spectroscopy, and thermal denaturation studies, we evaluate the importance of residues in the N_ext-RRM interface and

SUBMITTER: Atsrim ES 

PROVIDER: S-EPMC12006756 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature