3UX3: Crystal Structure of Domain-Swapped Fam96a minor dimer

Fam96a mRNA, which encodes a mammalian DUF59 protein, is enriched in macrophages. Recombinant human Fam96a forms stable monomers and dimers in solution. Crystal structures of these two forms revealed that each adopts a distinct type of domain-swapped dimer, one of which is stabilized by zinc binding. Two hinge loops control Fam96a domain swapping; both are flexible and highly conserved, suggesting that domain swapping may be a common feature of eukaryotic but not bacterial DUF59 proteins. The derived monomer fold of Fam96a diverges from that of bacterial DUF59 counterparts in that the C-terminal region of Fam96a is much longer and is positioned on the opposite side of the N-terminal core fold. The putative metal-binding site of bacterial DUF59 proteins is not conserved in Fam96a, but Fam96a interacts tightly in vitro with Ciao1, the cytosolic iron-assembly protein. Moreover, Fam96a and Ciao1 can be co-immunoprecipitated, suggesting that the interaction also occurs in vivo. Although predicted to have a signal peptide, it is shown that Fam96a is cytoplasmic. The data reveal that eukaryotic DUF59 proteins share intriguing characteristics with amyloidogenic proteins.
PDB ID: 3UX3Download
MMDB ID: 100068
PDB Deposition Date: 2011/12/3
Updated in MMDB: 2018/07
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 3UX3: dimeric; determined by author and by software (PISA)
Molecular Components in 3UX3
Label Count Molecule
Proteins (2 molecules)
Mip18 Family Protein Fam96a(Gene symbol: CIAO2A)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB