9TP6

Structure of LolA3 from Porphyromonas gingivalis

Summary for 9TP6

• Entry DOI: 10.2210/pdb9tp6/pdb
• Descriptor: Outer membrane lipoprotein-sorting protein, SULFATE ION, L(+)-TARTARIC ACID, ... (4 entities in total)
• Functional Keywords: lipoprotein transfer, transport protein
• Biological source: Porphyromonas gingivalis ATCC 33277
• Total number of polymer chains: 3
• Total formula weight: 96316.63

Authors

Jaiman, D.,Persson, K. (deposition date: 2025-12-17, release date: 2026-02-18, Last modification date: 2026-06-03)

Primary citation

Jaiman, D.,Hirohata, M.,Hasegawa, Y.,Persson, K.
Identification of a LolB-like protein in Porphyromonas gingivalis reveals selective LolA-LolB pairing.
Sci Rep, 16:-, 2026

PubMed Abstract: The lipoprotein transport (Lol) system is essential for outer membrane biogenesis in Gram-negative bacteria, yet its composition and organization vary markedly across bacterial phyla. While lipoprotein transport via the Lol pathway has been extensively characterized in , its components in the Bacteroidota phylum remain poorly understood. , a major periodontal pathogen has long been thought to lack the outer membrane lipoprotein insertase LolB, leaving the mechanism of lipoprotein insertion unclear. Here, we have identified and characterized a LolB-like protein in (LolB-PG). We determined its crystal structure at 2.1 Å resolution and revealed a conserved LolB fold but with an enlarged and more accessible lipid-binding cleft compared to proteobacterial homologs. Biophysical analyses demonstrate that LolB-PG selectively interacts with the cognate periplasmic chaperone LolA but not with the paralog LolA3, indicating a conserved yet specific LolA–LolB pairing. Deletion of the gene encoding LolBPG did not affect bacterial growth or the assembly, localization, or formation of type-V fimbriae—which are polymerized from lipoproteins— suggesting the existence of alternative lipoprotein trafficking routes in . Together, our findings reveal that Bacteroidota encode a functional LolB-like protein and highlight diversification of lipoprotein transport pathways beyond well-studied γ-proteobacteria.

PubMed: 42020509
DOI: 10.1038/s41598-026-49975-1

Experimental method

X-RAY DIFFRACTION (2.32 Å)