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)

Citation:
Abstract
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)
4
Soluble Cytochrome B562
Molecule annotation
Chemicals (8 molecules)
1
4
2
4
* Click molecule labels to explore molecular sequence information.

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