The role of cupric in maintaining the structure of CopC

Abstract

The CopC protein from pseudomonas syringae pathovar tomato is expressed as one of four proteins encoded by the operon CopABCD that is responsible for copper resistance. And there are one tryptophan (83), one tyrosine (79), and three phenylalanines (35, 43, 99) in apoCopC. The fluorescence peak of apoCopC is located near 320 nm, and the peak shifts toward 353 nm in the presence of 10 mol·L −1 urea with excitation at 280 nm. Using urea as a chemical agent, the conformational stabilities of apoCopC and were monitored by fluorescence spectrum in 20 mmol·L −1 phosphate buffer and 100 mmol·L −1 sodium chloride at pH 6.0. The free energy of stabilization for apoCopC and is 16.29±0.65 kJ·mol −1 and 26.26±0.35 kJ·mol −1 , respectively. The distance between the tryptophan residue and the Cu 2+ in has been studied by observing Förster type nonradiative energy transfer. And it is calculated to be 11.6 Å.

Conformational stability of CopC and roles of residues Tyr79 and Trp83

“…However, the binding sites of CopC can also be occupied by other transition metal ions, although the affinity is lower than that of copper ions. For example, Hg(II) ions can bind to both sites, whereas Ag(I) only binds to the Cu(I) site . Research suggests that cis‐Pt(NH 3 ) 2 Cl 2 (cisplatin) occupies the Cu(I) site, specifically in the 1:1 Pt–CopC adducts …”

“…For example, Hg(II) ions can bind to both sites, 21 whereas Ag(I) only binds to the Cu(I) site. 22 Research suggests that cis-Pt(NH 3 ) 2 Cl 2 (cisplatin) occupies the Cu(I) site, specifically in the 1:1 Pt-CopC adducts. 23 The stability of small globular proteins is a problem that is of outmost interest in biochemistry and biophysics, as demonstrated in the literature.…”

The Stability of a Three-State Unfolding Protein

“…The important role of the tryptophan residue 83 is not only in using as a fluorescence probe but also in keeping the -sandwich hydrophobic structure. The thermodynamic stability apoCopC can be investigated at pH 7.4 by monitoring the fluorescence intensity at around 405 nm [25,29,30]. As known Cu 2+ -CopC and Hg 2+ -CopC-Hg 2+ are prepared by adding Cu(II) or Hg(II).…”

The Comparative Numerical Experiments of Frequency Features for Earthquake Responds in Liquefiable Field and Elastic Field

“…In which, Biot (1956) proposed the basic equations described the dynamic properties of saturated porous media, Dynamic consolidation equation has been widely used in the dynamic analysis of soil. Biot consolidation equation is three-dimensional dynamic consolidation equation which accurately reflected the relationship between the pore water pressure dissipation and the deformation of soil skeleton from the more stringent mechanism derivation [5]. The Saturated Sandy Soil Liquefaction Determination Criterion in General Stress Conditions.…”