N. meningitidis 1681 is a member of the FinO family of RNA chaperones

作者：Chaulk Steven; Lu Jun; Tan Kemin; Arthur David C; Edwards Ross A; Frost Laura S; Joachimiak Andrzej; Glover J N Mark^*

来源：RNA Biology, 2010, 7(6): 812-819.

DOI：10.4161/rna.7.6.13688

• FinO
• plasmid conjugation
• RNA chaperone
• sRNA
• antisense RNA

The conjugative transfer of F-like plasmids between bacteria is regulated by the plasmid-encoded RNA chaperone, FinO, which facilitates sense-antisense RNA interactions to regulate plasmid gene expression. FinO was thought to adopt a unique structure, however many putative homologs have been identified in microbial genomes and are considered members of the FinO_conjugation_repressor superfamily. We were interested in determining whether other members were also able to bind RNA and promote duplex formation, suggesting that this motif does indeed identify a putative RNA chaperone. We determined the crystal structure of the N. meningitidis MC58 protein NMB1681. It revealed striking similarity to FinO, with a conserved fold and a large, positively charged surface that could function in RNA interactions. Using assays developed to study FinO-FinP sRNA interactions, NMB1681, like FinO, bound tightly to FinP RNA stem-loops with short 5' and 3' single-stranded tails but not to ssRNA. It also was able to catalyze strand exchange between an RNA duplex and a complementary single-strand, and facilitated duplexing between complementary RNA hairpins. Finally, NMB1681 was able to rescue a finO deficiency and repress F plasmid conjugation. This study strongly suggests that NMB1681 is a FinO-like RNA chaperone that likely regulates gene expression through RNA-based mechanisms in N. meningitidis.

• 出版日期2010-12