4G1A

Metal-binding properties of a self-assembled coiled coil: formation of a polynuclear Cd-thiolated cluster


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 

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Literature

Metal-binding properties and structural characterization of a self-assembled coiled coil: Formation of a polynuclear Cd-thiolate cluster.

Zaytsev, D.V.Morozov, V.A.Fan, J.Zhu, X.Mukherjee, M.Ni, S.Kennedy, M.A.Ogawa, M.Y.

(2012) J Inorg Biochem 119C: 1-9

  • DOI: 10.1016/j.jinorgbio.2012.10.010
  • Primary Citation of Related Structures:  
    4G1A

  • PubMed Abstract: 
  • This paper describes the design, characterization, and metal-binding properties of a 32-residue polypeptide called AQ-C16C19. The sequence of this peptide is composed of four repeats of the seven residue sequence Ile-Ala-Ala-Leu-Glu-Gln-Lys but with ...

    This paper describes the design, characterization, and metal-binding properties of a 32-residue polypeptide called AQ-C16C19. The sequence of this peptide is composed of four repeats of the seven residue sequence Ile-Ala-Ala-Leu-Glu-Gln-Lys but with a Cys-X-X-Cys metal-binding motif substituted at positions 16-19. Size exclusion chromatography with multiangle light scattering detection (SEC-MALS) and circular dichroism (CD) spectroscopy studies showed that the apo peptide exhibits a pH-dependent oligomerization state in which a three-stranded α-helical coiled coil is dominant between pH5.4 and 8.5. The Cd(2+)-binding properties of the AQ-C16C19 peptide were studied by ultraviolet-visible spectroscopy (UV-vis), electrospray ionization mass spectrometry (ESI MS), and (113)Cd NMR techniques. The holoprotein was found to contain a polynuclear cadmium-thiolate center formed within the hydrophobic core of the triple-stranded α-helical coiled-coil structure. The X-ray crystal structure of the Cd-loaded peptide, resolved at 1.85Å resolution, revealed an adamantane-like configuration of the polynuclear metal center consisting of four cadmium ions, six thiolate sulfur ligands from cysteine residues and four oxygen-donor ligands. Three of these are from glutamic acid residues and one is from an exogenous water molecule. Thus, each cadmium ion is coordinated in a distorted tetrahedral S(3)O geometry. The metal cluster was found to form cooperatively at pH5.4 but in a stepwise fashion at pH>7. The results demonstrate that synthetic coiled-coils can be designed to incorporate multinuclear metal clusters, a proof-of-concept for their potential use in developing synthetic metalloenzymes and multi-electron redox agents.


    Organizational Affiliation

    Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43403, United States.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
AQ-C16C19 peptideABC32synthetic constructMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CD
Query on CD

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A, B, C
CADMIUM ION
Cd
WLZRMCYVCSSEQC-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 30.762α = 90
b = 35.204β = 97.49
c = 64.123γ = 90
Software Package:
Software NamePurpose
PROTEUM PLUSdata collection
SHELXSphasing
REFMACrefinement
SAINTdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-12-05
    Type: Initial release