3ENT: Crystal Structure Of Nitrollin, A Betagamma-crystallin From Nitrosospira Multiformis-in Alternate Space Group (p65)

The betagamma-crystallin superfamily has a well-characterized protein fold, with several members found in both prokaryotic and eukaryotic worlds. A majority of them contain two betagamma-crystallin domains. A few examples, such as ciona crystallin and spherulin 3a exist that represent the eukaryotic single-domain proteins of this superfamily. This study reports the high-resolution crystal structure of a single-domain betagamma-crystallin protein, nitrollin, from the ammonium-oxidizing soil bacterium Nitrosospira multiformis. The structure retains the characteristic betagamma-crystallin fold despite a very low sequence identity. The protein exhibits a unique case of homodimerization in betagamma-crystallins by employing its N-terminal extension to undergo three-dimensional (3D) domain swapping with its partner. Removal of the swapped strand results in partial loss of structure and stability but not dimerization per se as determined using gel filtration and equilibrium unfolding studies. Overall, nitrollin represents a distinct single-domain prokaryotic member that has evolved a specialized mode of dimerization hitherto unknown in the realm of betagamma-crystallins.
PDB ID: 3ENTDownload
MMDB ID: 70543
PDB Deposition Date: 2008/9/26
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.14  Å
Source Organism:
Similar Structures:
Biological Unit for 3ENT: dimeric; determined by author and by software (PISA)
Molecular Components in 3ENT
Label Count Molecule
Proteins (2 molecules)
Putative Uncharacterized Protein
Molecule annotation
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