LAUSR

ABSTRACT PGRPs (Peptidoglycan recognition proteins) could recognize peptidoglycan and play vital roles in innate immunity among different animals. Till present, the functions of PGRP have been studied in various animals, but few reports have studied the amphibian PGRPs. In the current research, a short type PGRP was identified from Chinese giant salamander and its involvement in the innate immunity was studied. The ORF of AdPGRP‐SC2 cDNA was 573 bp, which encoded 190 amino acids, and contained a PGRP and an amidase_2 domain. The qPCR analysis revealed that AdPGRP‐SC2 mRNA transcripts expressed in different tissues, with the highest expression level in muscle, intestine and spleen. Results of immune challenges with peptidoglycan (PGN) demonstrated that expression patterns of AdPGRP‐SC2 were significantly up‐regulated in erythrocyte and spleen at the early injection stage. The recombinant AdPGRP‐SC2 protein was successfully produced and purified, and it could show binding affinity to different bacteria. In the presence of Zn2+, the rAdPGRP‐SC2 could exhibit a broad PAMPs binding activities, strongly agglutinate bacteria and exhibit amidase enzyme activity. Collectively, these data indicate AdPGRP‐SC2 could act as PRR to recognize the invading microorganisms and as the antimicrobial effectors during the innate immune response of A. davidianus. HIGHLIGHTSThe PGRP‐SC2 gene was identified and characterized in Andrias davidianus.AdPGRP‐SC2 was ubiquitously expressed in all tested tissues.AdPGRP‐SC2 could be up‐regulated in hemocyte and spleen after peptidoglycan injection.Recombinant AdPGRP‐SC2 could bind to different bacteria and exhibited a broad PAMPs binding activities.RPGRP‐SC2 could strongly agglutinate bacteria and exhibit amidase enzyme activity.