Download MendeleyThe bacterial cell division protein fragment E FtsN binds to and activates the major peptidoglycan synthase PBP1b.
Boes, A., Kerff, F., Herman, R., Touze, T., Breukink, E., Terrak, M.(2020) J Biol Chem 295: 18256-18265
- PubMed: 33109614
- DOI: https://doi.org/10.1074/jbc.RA120.015951
- Primary Citation of Related Structures:
6YN0 - PubMed Abstract:
Peptidoglycan (PG) is an essential constituent of the bacterial cell wall. During cell division, the machinery responsible for PG synthesis localizes mid-cell, at the septum, under the control of a multiprotein complex called the divisome. In Escherichia coli , septal PG synthesis and cell constriction rely on the accumulation of FtsN at the division site. Interestingly, a short sequence of FtsN (Leu 75 -Gln 93 , known as E FtsN) was shown to be essential and sufficient for its functioning in vivo , but what exactly this sequence is doing remained unknown. Here, we show that E FtsN binds specifically to the major PG synthase PBP1b and is sufficient to stimulate its biosynthetic glycosyltransferase (GTase) activity. We also report the crystal structure of PBP1b in complex with E FtsN, which demonstrates that E FtsN binds at the junction between the GTase and UB2H domains of PBP1b. Interestingly, mutations to two residues (R141A/R397A) within the E FtsN-binding pocket reduced the activation of PBP1b by FtsN but not by the lipoprotein LpoB. This mutant was unable to rescue the Δ ponB - ponA ts strain, which lacks PBP1b and has a thermosensitive PBP1a, at nonpermissive temperature and induced a mild cell-chaining phenotype and cell lysis. Altogether, the results show that E FtsN interacts with PBP1b and that this interaction plays a role in the activation of its GTase activity by FtsN, which may contribute to the overall septal PG synthesis and regulation during cell division.
Organizational Affiliation:
InBioS-Centre d'Ingénierie des Protéines, Liège University, Liège, Belgium.
