The advance of assembly of exopolysaccharide Psl biosynthesis machinery in Pseudomonas aeruginosa

• Published in: MicrobiologyOpen (Weinheim) 2019-10, Vol.8 (10), p.e857-n/a
• Main Authors: Wu, Huijun, Wang, Di, Tang, Maomao, Ma, Luyan Z.
• Format: Article
• Language: English
• Subjects: Antibiotics; Assembly; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; biofilm; Biofilms; Biosynthesis; Biosynthetic Pathways - genetics; E coli; Enzymes - genetics; Enzymes - metabolism; exopolysaccharide Psl; Exopolysaccharides; Experiments; Extracellular matrix; glycosyl hydrolase; Localization; Membranes; Microbial activity; Microorganisms; Motility; Opportunist infection; Original; Periplasm; Plasmids; Polymerization; Polysaccharides, Bacterial - biosynthesis; Protein Binding; Protein Interaction Maps; Proteins; Pseudomonas aeruginosa; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - metabolism; Studies; Two-Hybrid System Techniques
• ISSN: 2045-8827; 2045-8827
• DOI: 10.1002/mbo3.857

Biofilms are microbial communities embedded in extracellular matrix. Exopolysaccharide Psl (ePsl) is a key biofilm matrix component that initiates attachment, maintains biofilms architecture, and protects bacteria within biofilms of Pseudomonas aeruginosa, an opportunistic pathogen. There are at least 12 Psl proteins involved in the biosynthesis of this exopolysaccharide. However, it remains unclear about the function of each Psl protein and how these proteins work together during the biosynthesis of ePsl. PslG has been characterized as a degrader of ePsl in extracellular or periplasm and PslD is predicted to be a transporter. In this study, we found that PslG and its glycoside hydrolytic activity were also involved in the biosynthesis of ePsl. PslG localized mainly in the inner membrane and some in the periplasm. The inner membrane association of PslG was critical for the biosynthesis of ePsl. The expression of PslA, PslD, and PslE helped PslG remain in the inner membrane. The bacterial two‐hybrid results suggested that PslE could interacted with either PslA, PslD, or PslG. The strongest interaction was found between PslE and PslD. Consistently, PslD was disabled to localize on the outer membrane in the ΔpslE strain, suggesting that the PslE‐PslD interaction affected the localization of PslD. Our results shed light on the assembly of ePsl biosynthesis machinery and suggested that the membrane‐associated PslG was a part of ePsl biosynthesis proteins complex. In this study, we shed light on the assembly of exopolysaccharide Psl (ePsl) biosynthesis machinery in Pseudomonas aeruginosa. We improve our understanding about the function of PslG, the interactions among Psl proteins and the effect of proteins interactions on the localization of Psl protein during ePsl biosynthesis .