Resonance Raman spectra of rubredoxin, desulforedoxin, and the synthetic analog Fe(S2-o-xyl)2: conformational effects

Abstract

enkephalin, eluted at 165 min, was collected and accounted for 92% of the starting material.(B) Bovine Growth Hormone Fragment (128)(129)(130)(131). The tetrapeptide Boc-Glu(OBzl)-Asp(OBzl)-Gly-Thr(Bzl)-OCH2-resin was synthesized from Boc-Thr(Bzl)-OCH2-resin (5 g, 0.22 mmol/g). Samples of 100-250 mg each were treated with different HF procedures as required.The results (Table VIII) were quantitated by ion-exchange chromatography on an AA-15 column (Beckman, 0.9 X 54 cm) attached on a Beckman 120B amino acid analyzer, eluted with pH 3.20 citrate buffer at 59 °C. The elution times of the peptides were /3-peptide 53 min, -peptide 70 min, and imide 135 min (Scheme VI).(C) Pentagastrin Amide. The pentapeptide Boc-Gly-Trp(For)-Met-(0)-Asp(0Bzl)-Phe-NH-CH(C6H5)-C6H4-0C0CH2-resin (3), was synthesized from a multidetachable benzhydrylamine-resin, prepared according to ref 46, 5 g, 0.18 mmol/g. Samples of 100-250 mg each were treated with different HF procedures as required. The results are summarized in Tables XII and XIII.

Synthesis and Characterization of Desulfovibrio gigas Rubredoxin and Rubredoxin Fragments

“…Two of these components are visible at room temperature (359 cm-' and 371 cm-' [40]) while all three components (348, 363 and 376cm-I) appear at low temperatures [40]. The splitting originates in coupling of the Fe-S stretching modes to deformational motion around the S-C,-C, bonds in particular, making the stretching bands sentitive monitors of the Fe-S-C,-C, conformation [39]. The resonance Raman spectrum of synthetic D. gigas oxidized rubredoxin is shown (Fig.…”

“…Well-resolved spectra of rubredoxins in high concentrations reveal notable distortion from the regular tetrahedral geometry [39,401, with four prominent peaks in the Fe-S stretching region (300-400 cm-'). The dominating breathing v, mode at 312 crn-.'…”

Observation of terahertz vibrations in Pyrococcus furiosus rubredoxin via impulsive coherent vibrational spectroscopy and nuclear resonance vibrational spectroscopy – interpretation by molecular mechanics

“…They are key electron donors in alkane oxidation pathways [2] and in superoxide reduction [3]. Apart from their biological significance, rubredoxins have often been employed as model systems for the development of spectroscopic techniques such as resonance Raman spectroscopy [4,5], EXAFS [6], L-edge spectroscopy [7], X-ray magnetic circular dichroism -XMCD [8], high-resolution X-ray fluorescence [9], resonance energy transfer -RET [10], optically detected electron paramagnetic resonance -ODEPR [11], and nuclear resonance vibrational spectroscopy -NRVS [12], that are ultimately employed on more complex metalloproteins. Rubredoxin from Pyrococcus furiosus (PfRd), the object of the current study, has an unfolding rate of $10 À6 s À1 at 100°C [13] and has served as a model for structural features underlying thermal stability in hyperthermophilic proteins.…”

Quantum-Mechanical Study of Lead Coordination in Sulfur-Rich Proteins: Mode and Structure Recognition in UV Resonance Raman Spectra

“…Similar trends of elevated metal-ligand frequencies in the protein environment vs. its modeled compounds are observed for other metals. For instance, the 314 cm −1 signal of Fe-S stretching mode observed in rubredoxin 7 was found at 298 cm −1 in the model Fe(S 2 - o -xyl) 2 ] − (ligand = o -xylene-α,α’-ditholate) complex 8e .…”

“…Apart from immense UVRR studies of the heme proteins and related metalloporphyrins, rubredoxin was one of the first biological molecules to which resonance Raman spectroscopy was applied to identify the metal-ligand stretching and bending modes and determine the tetrahedral coordination of the Fe(Cys) 4 domain 7 . Shortly after, the spectroscopic and structural characterization of [2Fe-2S], [4Fe-4S] and [3Fe-4S] cluster proteins successfully followed 8 . More recently, UVRR experiments were successfully applied to monitor the histidine and cysteine ligand environment in cupper-, cobalt- and cadmium-substituted zinc-binding peptides by resonant excitations to the ligand-to-metal charge transfer transitions 9 .…”