3M79: A Tetrameric Zn-Bound Cytochrome Cb562 Complex With Covalently And Non-Covalently Stabilized Interfaces Crystallized In The Presence Of Cu(Ii) And Zn(Ii)

Selective binding by metalloproteins to their cognate metal ions is essential to cellular survival. How proteins originally acquired the ability to selectively bind metals and evolved a diverse array of metal-centered functions despite the availability of only a few metal-coordinating functionalities remains an open question. Using a rational design approach (Metal-Templated Interface Redesign), we describe the transformation of a monomeric electron transfer protein, cytochrome cb(562), into a tetrameric assembly ((C96)RIDC-1(4)) that stably and selectively binds Zn(2+) and displays a metal-dependent conformational change reminiscent of a signaling protein. A thorough analysis of the metal binding properties of (C96)RIDC-1(4) reveals that it can also stably harbor other divalent metals with affinities that rival (Ni(2+)) or even exceed (Cu(2+)) those of Zn(2+) on a per site basis. Nevertheless, this analysis suggests that our templating strategy simultaneously introduces an increased bias toward binding a higher number of Zn(2+) ions (four high affinity sites) versus Cu(2+) or Ni(2+) (two high affinity sites), ultimately leading to the exclusive selectivity of (C96)RIDC-1(4) for Zn(2+) over those ions. More generally, our results indicate that an initial metal-driven nucleation event followed by the formation of a stable protein architecture around the metal provides a straightforward path for generating structural and functional diversity.
PDB ID: 3M79Download
MMDB ID: 82824
PDB Deposition Date: 2010/3/16
Updated in MMDB: 2010/07
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 3M79: tetrameric; determined by author and by software (PISA)
Molecular Components in 3M79
Label Count Molecule
Proteins (4 molecules)
Soluble Cytochrome B562
Molecule annotation
Chemicals (8 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB