# RNA recognition by minimal ProQ from Neisseria meningitidis

## TL;DR

This study explores how a simplified RNA-binding protein from Neisseria meningitidis recognizes RNA by analyzing its interactions with different RNA ligands.

## Contribution

The study reveals specific RNA structural features required for tight binding by minimal ProQ from Neisseria meningitidis.

## Key findings

- N. meningitidis ProQ binds to the lower part of RNA hairpins and requires single-stranded regions on either side.
- The optimal RNA sequences for binding differ between rpmG-3′ and AniS RNAs.
- The 2′-OH and 3′-OH groups of the terminal ribose are important for RNA binding.

## Abstract

Neisseria meningitidis minimal ProQ is a global RNA-binding protein belonging to the family of FinO-domain proteins. The N. meningitidis ProQ consists only of the FinO domain accompanied by short N- and C-terminal extensions. To better understand how this minimal FinO-domain protein recognizes RNAs, we compared its binding to seven different natural RNA ligands of this protein. Next, two of these RNAs, rpmG-3′ and AniS, were subject to further mutational studies. The data showed that N. meningitidis ProQ binds the lower part of the intrinsic transcription terminator hairpin, and that the single-stranded sequences on the 5′ and 3′ side of the terminator stem are required for tight binding. However, the specific lengths of 5′ and 3′ RNA sequences required for optimal binding differed between the two RNAs. Additionally, our data show that the 2′-OH and 3′-OH groups of the 3′ terminal ribose contribute to RNA binding by N. meningitidis ProQ. In summary, the minimal ProQ protein from N. meningitidis has generally similar requirements for RNA binding as the isolated FinO domains of other proteins of this family, but differs from them in detailed RNA features that are optimal for specific RNA recognition.