6BRS image
Entry Detail
PDB ID:
6BRS
Keywords:
Title:
The Crystal Structure of the Ferredoxin Protease FusC in complex with Arabidopsis Ferredoxin, Ethylmercury phosphate soaked dataset
Biological Source:
PDB Version:
Deposition Date:
2017-11-30
Release Date:
2018-06-20
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.24
R-Value Work:
0.18
R-Value Observed:
0.19
Space Group:
P 2 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Putative zinc protease
Chain IDs:A
Chain Length:899
Number of Molecules:1
Biological Source:Pectobacterium atrosepticum (strain SCRI 1043 / ATCC BAA-672)
Polymer Type:polypeptide(L)
Description:unidentified Ferredoxin peptide
Chain IDs:D (auth: E)
Chain Length:4
Number of Molecules:1
Biological Source:Arabidopsis thaliana
Polymer Type:polypeptide(L)
Description:Ferredoxin-2, chloroplastic
Chain IDs:B (auth: F), C
Chain Length:104
Number of Molecules:2
Biological Source:Arabidopsis thaliana
Primary Citation
FusC, a member of the M16 protease family acquired by bacteria for iron piracy against plants.
PLoS Biol. 16 e2006026 e2006026 (2018)
PMID: 30071011 DOI: 10.1371/journal.pbio.2006026

Abstact

Iron is essential for life. Accessing iron from the environment can be a limiting factor that determines success in a given environmental niche. For bacteria, access of chelated iron from the environment is often mediated by TonB-dependent transporters (TBDTs), which are β-barrel proteins that form sophisticated channels in the outer membrane. Reports of iron-bearing proteins being used as a source of iron indicate specific protein import reactions across the bacterial outer membrane. The molecular mechanism by which a folded protein can be imported in this way had remained mysterious, as did the evolutionary process that could lead to such a protein import pathway. How does the bacterium evolve the specificity factors that would be required to select and import a protein encoded on another organism's genome? We describe here a model whereby the plant iron-bearing protein ferredoxin can be imported across the outer membrane of the plant pathogen Pectobacterium by means of a Brownian ratchet mechanism, thereby liberating iron into the bacterium to enable its growth in plant tissues. This import pathway is facilitated by FusC, a member of the same protein family as the mitochondrial processing peptidase (MPP). The Brownian ratchet depends on binding sites discovered in crystal structures of FusC that engage a linear segment of the plant protein ferredoxin. Sequence relationships suggest that the bacterial gene encoding FusC has previously unappreciated homologues in plants and that the protein import mechanism employed by the bacterium is an evolutionary echo of the protein import pathway in plant mitochondria and plastids.

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