MagC is a NplC/P60‐like member of the $\alpha$‐2‐macroglobulin Mag complex of $Pseudomonas\ aeruginosa$ that interacts with peptidoglycan

Samira Zouhir (1) , Carlos Contreras‐martel (2) , Daniel Maragno Trindade (1) , Ina Attrée (3) , Andréa Dessen (2, 1) , Pauline Macheboeuf (2)

1 Brazilian Biosciences National Laboratory (LNBio)
2 IBS - UMR 5075 - Institut de biologie structurale
3 IBS-PBRC - Groupe Pathogenèse Bactérienne et Réponses Cellulaires / Bacterial Pathogenesis and Cellular Responses Group

Bacterial $\alpha$-2 macroglobulins (A2Ms) structurally resemble the large spectrum protease inhibitors of the eukaryotic immune system. In $Pseudomonas\ aeruginosa$, MagD acts as an A2M and is expressed within a six-gene operon encoding the MagA-F proteins. In this work, we employ isothermal calorimetry (ITC), analytical ultracentrifugation (AUC), and X-ray crystallography to investigate the function of MagC and show that MagC associates with the macroglobulin complex and with the peptidoglycan (PG). However, the catalytic residues of MagC display an inactive conformation that could suggest that it binds to PG but does not degrade it. We hypothesize that MagC could serve as an anchor between the MagD macroglobulin and the PG and could provide stabilization and/or regulation for the entire complex.

Domaines: Bactériologie; Biologie moléculaire; Sciences du Vivant [q-bio]

Samira Zouhir, Carlos Contreras‐martel, Daniel Maragno Trindade, Ina Attrée, Andréa Dessen, et al.. MagC is a NplC/P60‐like member of the $\alpha$‐2‐macroglobulin Mag complex of $Pseudomonas\ aeruginosa$ that interacts with peptidoglycan. FEBS Letters, 2021, ⟨10.1002/1873-3468.14148⟩. ⟨hal-03273605⟩