7BK5 image
Deposition Date 2021-01-15
Release Date 2021-07-07
Last Version Date 2024-01-31
Entry Detail
PDB ID:
7BK5
Title:
PfCopC mutant - E27A
Biological Source:
Method Details:
Experimental Method:
Resolution:
1.54 Å
R-Value Free:
0.23
R-Value Work:
0.20
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Putative copper resistance protein
Gene (Uniprot):PFLU_3946
Mutations:E27A
Chain IDs:A (auth: AAA)
Chain Length:97
Number of Molecules:1
Biological Source:Pseudomonas fluorescens (strain SBW25)
Primary Citation
Copper binding and reactivity at the histidine brace motif: insights from mutational analysis of the Pseudomonas fluorescens copper chaperone CopC.
Febs Lett. 595 1708 1720 (2021)
PMID: 33896006 DOI: 10.1002/1873-3468.14092

Abstact

The histidine brace (His-brace) is a copper-binding motif that is associated with both oxidative enzymes and proteinaceous copper chaperones. Here, we used biochemical and structural methods to characterize mutants of a His-brace-containing copper chaperone from Pseudomonas fluorescens (PfCopC). A total of 15 amino acid variants in primary and second-sphere residues were produced and characterized in terms of their copper binding and redox properties. PfCopC has a very high affinity for Cu(II) and also binds Cu(I). A high reorganization barrier likely prevents redox cycling and, thus, catalysis. In contrast, mutations in the conserved second-sphere Glu27 enable slow oxidation of ascorbate. The crystal structure of the variant E27A confirmed copper binding at the His-brace. Unexpectedly, Asp83 at the equatorial position was shown to be indispensable for Cu(II) binding in the His-brace of PfCopC. A PfCopC mutant that was designed to mimic the His-brace from lytic polysaccharide monooxygenase-like family X325 did not bind Cu(II), but was still able to bind Cu(I). These results highlight the importance of the proteinaceous environment around the copper His-brace for reactivity and, thus, the difference between enzyme and chaperone.

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