5AZ7: Crystal Structure Of Mbp-tom20 Fusion Protein With A 4-residue Spacer In The Connector Helix

Contacts with neighboring molecules in protein crystals inevitably restrict the internal motions of intrinsically flexible proteins. The resultant clear electron densities permit model building, as crystallographic snapshot structures. Although these still images are informative, they could provide biased pictures of the protein motions. If the mobile parts are located at a site lacking direct contacts in rationally designed crystals, then the amplitude of the movements can be experimentally analyzed. We propose a fusion protein method, to create crystal contact-free space (CCFS) in protein crystals and to place the mobile parts in the CCFS. Conventional model building fails when large amplitude motions exist. In this study, the mobile parts appear as smeared electron densities in the CCFS, by suitable processing of the X-ray diffraction data. We applied the CCFS method to a highly mobile presequence peptide bound to the mitochondrial import receptor, Tom20, and a catalytically relevant flexible segment in the oligosaccharyltransferase, AglB. These two examples demonstrated the general applicability of the CCFS method to the analysis of the spatial distribution of motions within protein molecules.
PDB ID: 5AZ7Download
MMDB ID: 135422
PDB Deposition Date: 2015/9/27
Updated in MMDB: 2016/03
Experimental Method:
x-ray diffraction
Resolution: 1.96  Å
Similar Structures:
Biological Unit for 5AZ7: monomeric; determined by author
Molecular Components in 5AZ7
Label Count Molecule
Protein (1 molecule)
Maltose-binding Periplasmic Protein,mitochondrial Import Receptor Subunit Tom20 Homolog
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

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