6MCD image
Entry Detail
PDB ID:
6MCD
Keywords:
Title:
Crystal Structure of tris-thiolate Pb(II) complex with adjacent water in a de novo Three Stranded Coiled Coil Peptide
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2018-08-31
Release Date:
2020-03-04
Method Details:
Experimental Method:
Resolution:
1.50 Å
R-Value Free:
0.20
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
H 3 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Pb(II)(GRAND Coil Ser L12CL16A)-
Chain IDs:A
Chain Length:38
Number of Molecules:1
Biological Source:synthetic construct
Primary Citation
Heteromeric three-stranded coiled coils designed using a Pb(II)(Cys)3template mediated strategy.
Nat.Chem. 12 405 411 (2020)
PMID: 32123337 DOI: 10.1038/s41557-020-0423-6

Abstact

Three-stranded coiled coils are peptide structures constructed from amphipathic heptad repeats. Here we show that it is possible to form pure heterotrimeric three-stranded coiled coils by combining three distinct characteristics: (1) a cysteine sulfur layer for metal coordination, (2) a thiophilic, trigonal pyramidal metalloid (Pb(II)) that binds to these sulfurs and (3) an adjacent layer of reduced steric bulk generating a cavity where water can hydrogen bond to the cysteine sulfur atoms. Cysteine substitution in an a site yields Pb(II)A2B heterotrimers, while d sites provide pure Pb(II)C2D or Pb(II)CD2 scaffolds. Altering the metal from Pb(II) to Hg(II) or shifting the relative position of the sterically less demanding layer removes heterotrimer specificity. Because only two of the eight or ten hydrophobic layers are perturbed, catalytic sites can be introduced at other regions of the scaffold. A Zn(II)(histidine)3(H2O) centre can be incorporated at a remote location without perturbing the heterotrimer selectivity, suggesting a unique strategy to prepare dissymmetric catalytic sites within self-assembling de novo-designed proteins.

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