2GBT: C6A/C111A CuZn Superoxide dismutase

The gain of neurotoxic function in amyotrophic lateral sclerosis (ALS) has been linked to misfolding of the homodimeric enzyme Cu/Zn superoxide dismutase (SOD). Here, we present the crystal structure of fully cysteine-depleted human SOD (SOD(CallA)), representing a reduced, marginally stable intermediate on the folding pathway in vivo that has also been implicated as neurotoxic precursor state. A hallmark of this species is that it fails to dimerize and becomes trapped as a monomer in the absence of the active-site metals. The crystallographic data show that removal of the C57-C146 disulphide bond sets free the interface loop IV in the apo protein, whereas the same loop remains unaffected in the holo protein. Thus, the low dimerisation propensity of disulphide-reduced apoSOD seems to be of entropic origin due to increased loop flexibility in the monomeric state: in the disulphide-reduced holo protein this gain in configurational entropy upon splitting of the dimer interface is reduced by the metal coordination.
PDB ID: 2GBTDownload
MMDB ID: 43331
PDB Deposition Date: 2006/3/11
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 2GBT: dimeric; determined by author and by software (PISA)
Molecular Components in 2GBT
Label Count Molecule
Proteins (2 molecules)
Superoxide Dismutase [cu-zn](Gene symbol: SOD1)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB