2BYU: Negative Stain Em Reconstruction Of M.tuberculosis Acr1(hsp 16.3) Fitted With Wheat Shsp Dimer

Small heat shock proteins are a ubiquitous and diverse family of stress proteins that have in common an alpha-crystallin domain. Mycobacterium tuberculosis has two small heat shock proteins, Acr1 (alpha-crystallin-related protein 1, or Hsp16.3/16-kDa antigen) and Acr2 (HrpA), both of which are highly expressed under different stress conditions. Small heat shock proteins form large oligomeric assemblies and are commonly polydisperse. Nanoelectrospray mass spectrometry showed that Acr2 formed a range of oligomers composed of dimers and tetramers, whereas Acr1 was a dodecamer. Electron microscopy of Acr2 showed a variety of particle sizes. Using three-dimensional analysis of negative stain electron microscope images, we have shown that Acr1 forms a tetrahedral assembly with 12 polypeptide chains. The atomic structure of a related alpha-crystallin domain dimer was docked into the density to build a molecular structure of the dodecameric Acr1 complex. Along with the differential regulation of these two proteins, the differences in their quaternary structures demonstrated here supports their distinct functional roles.
PDB ID: 2BYUDownload
MMDB ID: 126561
PDB Deposition Date: 2005/8/5
Updated in MMDB: 2017/09
Experimental Method:
electron microscopy
Resolution: 16.5  Å
Source Organism:
Similar Structures:
Biological Unit for 2BYU: dodecameric; determined by author and by software (PISA)
Molecular Components in 2BYU
Label Count Molecule
Proteins (12 molecules)
Heat Shock Protein 16.9b(Gene symbol: hsp16.9B)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB