Copper Storage Protein From
            <i>Streptomyces Lividans</i>

Worrall, J.A.R.

doi:10.1002/9781119951438.eibc2777

Cited by 1 publication

(1 citation statement)

References 56 publications

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“…Further, it must be handled in an anaerobic atmosphere to avoid oxidation. Thus, there are limited methods for reliable determination of the Cu(I) affinity to peptides and proteins. , While the use of BCA competition to determine the apparent affinities is potentially problematic, it is still commonly used to determine the approximate relative affinities of peptides and proteins for Cu(I). ,− We reasoned that the most likely interfering factors in previous determinations of the apparent formation constants for the Cu(I)HSA and Cu(I)Ctr 1–14 affinities might be the presence of uncharacterized ternary complexes that either are spectroscopically silent or have spectral features similar to those of Cu(BCA) 2 . ,, Further, previous determinations of the Cu(I) affinity of the two polypeptides were conducted under slightly different conditions. , Therefore, we found it prudent to reinspect the interactions of Cu(I) with HSA and Ctr 1–14 , even using the limited tool of BCA as the competing ligand. We reasoned that interference by ternary complexes should be less severe at lower concentration, and so we reinvestigated the solution competition of HSA and Ctr 1–14 with Cu(BCA) 2 at approximately 10-fold lower concentration than was done previously.…”

Section: Resultsmentioning

confidence: 99%

Exploration of the Potential Role of Serum Albumin in the Delivery of Cu(I) to Ctr1

et al. 2023

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Human serum albumin (HSA) is the major copper (Cu) carrier in blood. The majority of previous studies that have investigated Cu interactions with HSA have focused primarily on the Cu(II) oxidation state. Yet, cellular Cu uptake by the human copper transport protein (Ctr1), a plasma membrane-embedded protein responsible for Cu uptake into cells, requires Cu(I). Recent in vitro work has determined that reducing agents, such as the ascorbate present in blood, are sufficient to reduce the Cu(II)HSA complex to form Cu(I)HSA and that Cu(I) is bound to HSA with pM affinity. The biological accessibility of Cu(I)HSA suggests that HSA-bound Cu(I) may be an unappreciated form of Cu cargo and a key player in extracellular Cu trafficking. To better understand Cu trafficking by HSA, we sought to investigate the exchange of Cu(I) from HSA to a model peptide of the Cu-binding ectodomain of Ctr1. In this study, we used X-ray absorption near-edge spectroscopy to show that Cu(I) becomes more highly coordinated as increasing amounts of the Ctr1–14 model peptide are added to a solution of Cu(I)HSA. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to further characterize the interaction of Cu(I)HSA with Ctr1–14 by determining the ligands coordinating Cu(I) and their bond lengths. The EXAFS data support that some Cu(I) likely undergoes complete transfer from HSA to Ctr1–14. This finding of HSA interacting with and releasing Cu(I) to an ectodomain model peptide of Ctr1 suggests a mechanism by which HSA delivers Cu(I) to cells under physiological conditions.

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