Two Novel Short Peptidoglycan Recognition Proteins (PGRPs) From the Deep Sea Vesicomyidae Clam Archivesica packardana: Identification, Recombinant Expression and Bioactivity

Abstract

Vesicomyidae clams are common species living in cold seeps, which incorporates symbiotic bacteria into their body maintaining endosymbiosis relationship. As members of pattern recognition receptor (PRR) family, peptidoglycan recognition proteins (PGRPs) recognize pathogen associated molecular patterns and play an important role in innate immunity. In present study, two short PGRPs (ApPGRP-1 and -2) were first identified from Vesicomyidae clam Archivesica packardana. Sequences analysis showed that they have both conserved Zn2+ binding sites (H-H-C) and amidase catalytic sites (H-Y-H-T-C), and phylogenetic tree indicated that they clustered with short PGRPs of other molluscs. PGN assay showed that ApPGRPs could bind Lys-type PGN from Staphylococcus aureus and Dap-type PGN from Bacillus subtilis, and revealed amidase activity with selective zinc ion dependence. rApPGRP-1 and -2 (recombinant ApPGRP-1 and -2) could bind six bacteria with a broad spectrum and had both zinc-dependent and -independent bactericidal activity. ApPGRPs had the complete functions of effectors and partial functions of receptors from PGRPs. Further analyses showed that ApPGRPs from A. packardana might be involved in the endosymbiosis relationship between the host clam and endosymbiotic bacteria as a regulator. The results of these experiments suggested that ApPGRPs were involved in cold seep clams’ immune response. This study provides basic information for further research on the immune mechanisms of deep sea organisms.

Transcriptomic profile of symbiotic accessory nidamental gland during female maturation in bigfin reef squid

“…Furthermore, PGRP2 showed bactericidal activity in bigfin reef squid (Li et al, 2022) and Hawaiian bobtail squid (Troll et al, 2010). Other secreted PGRPs also showed bactericidal activity in different species, including some bivalves (Kong et al, 2018;Huang et al, 2019;Yang et al, 2019), teleosts (Li et al, 2007;Kim et al, 2010;Li et al, 2020), and mammals (Lu et al, 2006). Taken together, our data suggest that ANG-expressed Pgrp2 and Pgrp3l may participate in bacterial colonization and pigmentation during ANG growth in female bigfin reef squid.…”

Transcriptome Analysis Elucidates the Key Responses of Bryozoan Fredericella sultana during the Development of Tetracapsuloides bryosalmonae (Myxozoa)

“…We also identified some other important downregulated genes in the infected zooids such as peptidoglycan-binding protein (−125.94 fold) and chitotriosidase-1 (−37.05 fold). Peptidoglycan-binding protein is required as a cell surface receptor for peptidoglycan elicitor signaling leading to innate immunity of the host [ 35 ]. Downregulation of peptidoglycan-binding protein in the infected bryozoans may suggest a restructuring of the protein in response to oxidizing conditions, preventing activation of the IMD signal transduction pathway following parasite infection [ 36 ].…”