5had | pdb_00005had
Crystal structure of intermembrane space region of chloroplast protein ARC6
Structural highlights
FunctionARC6_ARATH Component of the plastid division machinery. Involved in the initiation of proplastid and plastid division (including chloroplasts, statoliths and leukoplasts). Promotes the assembly and/or stabilization of the plastid-dividing FtsZ ring, functioning as an antagonistic regulator of FtsZ dynamics against CDP1. Relays plastid division site position between stroma and outer surface via interactions with the stromal FtsZ ring and the outer membrane PDV2 that recruits cytoplasmic ARC5 ring. Required for plastid equatorial positioning of PDV2 and ARC5. May contribute to gravitropism in stems and hypocotyls. Seems to influence stromule (stroma-filled tubular extensions of the plastid envelope membrane) length and frequency.[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedChloroplasts divide by binary fission, which is accomplished by the simultaneous constriction of the FtsZ ring on the stromal side of the inner envelope membrane, and the ARC5 ring on the cytosolic side of the outer envelope membrane. The two rings are connected and coordinated mainly by the interaction between the inner envelope membrane protein ARC6 and the outer envelope membrane protein PDV2 in the intermembrane space. The underlying mechanism of this coordination is unclear to date. Here, we solved the crystal structure of the intermembrane space region of the ARC6-PDV2 complex. The results indicated that PDV2 inserts its carboxy terminus into a pocket formed in ARC6, and this interaction further induces the dimerization of the intermembrane space regions of two ARC6 molecules. A pdv2 mutant attenuating PDV2-induced ARC6 dimerization showed abnormal morphology of ARC6 rings and compromised chloroplast division in plant cells. Together, our data reveal that PDV2-induced dimerization of ARC6 plays a critical role in chloroplast division and provide insights into the coordination mechanism of the internal and external plastid division machineries. Structural insights into the coordination of plastid division by the ARC6-PDV2 complex.,Wang W, Li J, Sun Q, Yu X, Zhang W, Jia N, An C, Li Y, Dong Y, Han F, Chang N, Liu X, Zhu Z, Yu Y, Fan S, Yang M, Luo SZ, Gao H, Feng Y Nat Plants. 2017 Mar 1;3:17011. doi: 10.1038/nplants.2017.11. PMID:28248291[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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