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Publication Abstract from PubMed

A recent genetic study with Brucella abortus revealed the secretion activator gene A (SagA) as an autolysin component creating pores in the peptidoglycan (PGN) layer for the type IV secretion system (T4SS) and peptidoglycan hydrolase inhibitor A (PhiA) as an inhibitor of SagA. In this study, we determined the crystal structures of both SagA and PhiA. Notably, the SagA structure contained a PGN fragment in a space between the N- and C-terminal domains, showing the substrate-dependent hinge motion of the domains. The purified SagA fully hydrolyzed the meso-diaminopimelic acid (DAP)-type PGN, showing a higher activity than hen egg-white lysozyme. The PhiA protein exhibiting tetrameric assembly failed to inhibit SagA activity in our experiments. Our findings provide implications for the molecular basis of the SagA-PhiA system of B. abortus. The development of inhibitors of SagA would further contribute to controlling brucellosis by attenuating the function of T4SS, the major virulence factor of Brucella.

Structure and Function of the Autolysin SagA in the Type IV Secretion System of Brucella abortus.,Hyun Y, Baek Y, Lee C, Ki N, Ahn J, Ryu S, Ha NC Mol Cells. 2021 Jun 11. pii: molcells.2021.0011. doi:, 10.14348/molcells.2021.0011. PMID:34112742^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.