Investigation of the Copper Binding Site And the Role of Histidine As a Ligand in Riboflavin Binding Protein

Journal Article · Tue May 26 00:00:00 EDT 2009 · Inorg. Chem. 47:6867,2008

OSTI ID:953570

Smith, S R; Bencze, K Z; Russ, K A; Wasiukanis, K; Benore-Parsons, M; Stemmler, T L

Riboflavin Binding Protein (RBP) binds copper in a 1:1 molar ratio, forming a distinct well-ordered type II site. The nature of this site has been examined using X-ray absorption and pulsed electron paramagnetic resonance (EPR) spectroscopies, revealing a four coordinate oxygen/nitrogen rich environment. On the basis of analysis of the Cambridge Structural Database, the average protein bound copper-ligand bond length of 1.96 {angstrom}, obtained by extended x-ray absorption fine structure (EXAFS), is consistent with four coordinate Cu(I) and Cu(II) models that utilize mixed oxygen and nitrogen ligand distributions. These data suggest a Cu-O{sub 3}N coordination state for copper bound to RBP. While pulsed EPR studies including hyperfine sublevel correlation spectroscopy and electron nuclear double resonance show clear spectroscopic evidence for a histidine bound to the copper, inclusion of a histidine in the EXAFS simulation did not lead to any significant improvement in the fit.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 953570
• Report Number(s): SLAC-REPRINT-2009-313
• Journal Information: Inorg. Chem. 47:6867,2008, Journal Name: Inorg. Chem. 47:6867,2008 Journal Issue: 15 Vol. 47; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
BOND LENGTHS
COORDINATES
COPPER
CORRELATIONS
DATA
ELECTRON SPIN RESONANCE
ENDOR
ENVIRONMENT
FINE STRUCTURE
HISTIDINE
INCLUSIONS
LIGANDS
NITROGEN
OXYGEN
Other
OTHER
CHEM
PROTEINS
RIBOFLAVIN
SIMULATION
SPECTROSCOPY