4NDP: Crystal structure Molybdenum Storage Protein with fully Mo-loaded cavity

Citation:
Abstract
The molybdenum storage protein (MoSto) can store more than 100 Mo or W atoms as discrete polyoxometalate (POM) clusters. Here, we describe the three POM cluster sites along the threefold axis of the protein complex based on four X-ray structures with slightly different polyoxomolybdate compositions between 1.35 and 2 A resolution. In contrast to the Moalpha-out binding site occupied by an Mo3 cluster, the Moalpha-in and Mobeta binding sites contain rather weak and non-uniform electron density for the Mo atoms (but clearly identifiable by anomalous data), suggesting the presence of POM cluster ensembles and/or degradation products of larger aggregates. The "Moalpha-in cluster ensemble" was interpreted as an antiprism-like Mo6 species superimposed with an Mo7 pyramide and the "Mobeta cluster ensemble" as an Mo13 cluster (present mostly in a degraded form) composed of a pyramidal Mo7 and a Mo3 building block linked by three spatially separated MoOx units. Inside the ball-shaped Mo13 cluster sits an occluded central atom, perhaps a metal ion. POM cluster formation at the Moalpha-in and Mobeta sites appears to be driven by filtering out and binding/protecting self-assembled transient species complementary to the protein template.
PDB ID: 4NDPDownload
MMDB ID: 122334
PDB Deposition Date: 2013/10/27
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 4NDP: hexameric; determined by author and by software (PISA)
Molecular Components in 4NDP
Label Count Molecule
Proteins (6 molecules)
3
Molybdenum Storage Protein Subunit Beta
Molecule annotation
3
Molybdenum Storage Protein Subunit Alpha
Molecule annotation
Chemicals (22 molecules)
1
6
2
6
3
3
4
3
5
1
6
3
* Click molecule labels to explore molecular sequence information.

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