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Publication Abstract from PubMed

Encapsulin nanocompartments loaded with dedicated cargo proteins via unique targeting peptides, play a key role in stress resistance, iron storage and natural product biosynthesis. Mmp1 and cysteine desulfurase (Enc-CD) have been identified as the most abundant representatives of family 2 encapsulin systems. However, the molecular assembly, catalytic mechanism, and physiological functions of the Mmp1 encapsulin system have not been studied in detail. Here we isolate and characterize an Enc-CD-loaded Mmp1 encapsulin system from Mycobacterium smegmatis mc(2)155. The cryo-EM structure of the Mmp1 encapsulin and the crystal structure of the naked cargo Enc-CD have been determined. The structure shows that the Mmp1 protomer assembles two conformation models, the icosahedron (T = 1) and homodecamer, with the resolution of 2.60 A and 2.69 A. The Enc-CD at 2.10 A resolution is dimeric and loaded into the Mmp1 (T = 1) encapsulin through the N-terminal long disordered region. Mmp1 encapsulin protects Enc-CD against oxidation as well as to maintain structural stability. These studies provide new insights into the mechanism by which Enc-CD-loaded encapsulin stores sulfur and provides a framework for discovery of new anti-mycobacterial therapeutics.

The structural and functional analysis of mycobacteria cysteine desulfurase-loaded encapsulin.,Tang Y, Liu Y, Zhang M, Lan W, Ma M, Chen C, Wu S, Chen R, Yan Y, Feng L, Li Y, Guddat LW, Gao Y, Liu X, Rao Z Commun Biol. 2024 Dec 19;7(1):1656. doi: 10.1038/s42003-024-07299-8. PMID:39702509^[1]

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