The structural and functional analysis of mycobacteria cysteine desulfurase-loaded encapsulin

Abstract 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 e...

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Main Authors: Yanting Tang, Yanyan Liu, Mingjing Zhang, Weiqi Lan, Mengyuan Ma, Cheng Chen, Saibin Wu, Rong Chen, Yiran Yan, Lu Feng, Ying Li, Luke W. Guddat, Yan Gao, Xiang Liu, Zihe Rao
Format: Article
Language:English
Published: Nature Portfolio 2024-12-01
Series:Communications Biology
Online Access:https://doi.org/10.1038/s42003-024-07299-8
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Summary:Abstract 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 mc2155. 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 Å and 2.69 Å. The Enc-CD at 2.10 Å 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.
ISSN:2399-3642