5DIH: Structure Of Haliangium Ochraceum Bmc-t Ho-5812

Citation:
Abstract
Bacterial microcompartments (BMCs) are self-assembling organelles composed of a selectively permeable protein shell and encapsulated enzymes. They are considered promising templates for the engineering of designed bionanoreactors for biotechnology. In particular, encapsulation of oxidoreductive reactions requiring electron transfer between the lumen of the BMC and the cytosol relies on the ability to conduct electrons across the shell. We determined the crystal structure of a component protein of a synthetic BMC shell, which informed the rational design of a [4Fe-4S] cluster-binding site in its pore. We also solved the structure of the [4Fe-4S] cluster-bound, engineered protein to 1.8 A resolution, providing the first structure of a BMC shell protein containing a metal center. The [4Fe-4S] cluster was characterized by optical and EPR spectroscopies; it has a reduction potential of -370 mV vs the standard hydrogen electrode (SHE) and is stable through redox cycling. This remarkable stability may be attributable to the hydrogen-bonding network provided by the main chain of the protein scaffold. The properties of the [4Fe-4S] cluster resemble those in low-potential bacterial ferredoxins, while its ligation to three cysteine residues is reminiscent of enzymes such as aconitase and radical S-adenosymethionine (SAM) enzymes. This engineered shell protein provides the foundation for conferring electron-transfer functionality to BMC shells.
PDB ID: 5DIHDownload
MMDB ID: 136237
PDB Deposition Date: 2015/9/1
Updated in MMDB: 2016/05
Experimental Method:
x-ray diffraction
Resolution: 2.44  Å
Source Organism:
Similar Structures:
Biological Unit for 5DIH: trimeric; determined by author and by software (PISA)
Molecular Components in 5DIH
Label Count Molecule
Proteins (3 molecules)
3
Microcompartments Protein
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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