Molecular and Functional Characterization of MobK Protein—A Novel-Type Relaxase Involved in Mobilization for Conjugational Transfer of Klebsiella pneumoniae Plasmid pIGRK

Autor: Katarzyna Paulina Nowak, Agnieszka Sobolewska-Ruta, Agata Jagiełło, Anna Bierczyńska-Krzysik, Piotr Kierył, Paweł Wawrzyniak
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 22, Iss 10, p 5152 (2021)
Druh dokumentu: article
ISSN: 1422-0067
1661-6596
DOI: 10.3390/ijms22105152
Popis: Conjugation, besides transformation and transduction, is one of the main mechanisms of horizontal transmission of genetic information among bacteria. Conjugational transfer, due to its essential role in shaping bacterial genomes and spreading of antibiotics resistance genes, has been widely studied for more than 70 years. However, new and intriguing facts concerning the molecular basis of this process are still being revealed. Most recently, a novel family of conjugative relaxases (Mob proteins) was distinguished. The characteristic feature of these proteins is that they are not related to any of Mobs described so far. Instead of this, they share significant similarity to tyrosine recombinases. In this study MobK—a tyrosine recombinase-like Mob protein, encoded by pIGRK cryptic plasmid from the Klebsiella pneumoniae clinical strain, was characterized. This study revealed that MobK is a site-specific nuclease and its relaxase activity is dependent on both a conserved catalytic tyrosine residue (Y179) that is characteristic of tyrosine recombinases and the presence of Mg2+ divalent cations. The pIGRK minimal origin of transfer sequence (oriT) was also characterized. This is one of the first reports presenting tyrosine recombinase-like conjugative relaxase protein. It also demonstrates that MobK is a convenient model for studying this new protein family.
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