+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Spectral and electrochemical studies of cytochrome c peptide complexes

Journal of Biological Chemistry 253(9): 3265-3272

Spectral and electrochemical studies of cytochrome c peptide complexes

Hemepeptides 14-21, 11-21, 11-26, 1-38, 1-65, and 1-80 and non-hemepeptides 66-104, 67-104 (guanidinated) and 1-104 (apoprotein) were purified from horse heart cytochrome c. Addition of non-hemepeptide 1-104 to any of the ferrohemepeptides or addition of non-hemepeptides 66-104 or 67-104 to ferrohemepeptides 1-65 or 1-80 produces changes in the visible absorption spectrum of the ferrohemepeptides, indicating ligation of the S of methionine 80 in the non-hemepeptide with the heme Fe of the hemepeptide. The absorption spectra, circular dichroic spectra, formal potential and electron transfer capability of these peptide complexes were measured. Noncovalent peptide complexes 1-38:1-104, 1-65:1-104, and 1-80:1-104 and the covalent complex 1-65-66-104 exhibit the structural parameters and biological function characteristic of the native protein. These results suggest that the native tertiary structure can be generated from overlapping peptides. By contrast, noncovalent complexes 14-21:1-104, 11-21:1-104, 11-26:1-104, 1-65:67-104, and 1-80:66-104, while containing substantial secondary structure as judged by optical measurements, appear to have an exposed heme moiety in both oxidation states, resulting in a low formal potential and no biological function. Combination of ferrohemepeptide 1-65, having a homoserine lactone at position 65, with peptide 66-104, but not with peptide 67-104, produces a peptide linkage between the COOH terminus of the hemepeptide and the NH2 terminus of the non-hemepeptide. This comparison suggests that the peptides are precisely oriented in a noncovalent complex such that a peptide bond cannot be formed across the gap resulting from the absence of residue 66. Comparison of the properties of the noncovalent complex 1-65:66-104 with the covalent complex 1-65-66-104 indicates that, while both complexes in the ferro form have a native tertiary structure, the noncovalent complex in the ferri form is unable to stabilize a buried heme moiety or a methionine ligand. The noncovalent complex formed by hemepeptide 1-38 with non-hemepeptide 1-104 was studied in detail. The formation constants, KF,O and KF,R, for ligation of methionine 80 in the non-hemepeptide with the hemepeptide in both oxidation states are about 4 orders of magnitude greater than for ligation of methionine itself, with KF,R about 1 order of magnitude greater than KF,O. Analysis of the dependence of the formal potential of the hemepeptide on the concentration of non-hemepeptide present indicates that the major increase in potential results from insertion of the heme into its apolar crevice and not from ligation of the methionine.

Accession: 006459491

PMID: 205545

Related references

El-Asmy, A.A.; El-Gammal, O.A.; Saleh, H.S., 2008: Spectral, thermal, electrochemical and analytical studies on Cd(II) and Hg(II) thiosemicarbazone complexes. The coordination characteristic of the investigated thiosemicarbazones towards hazard pollutants, Cd(II) and Hg(II), becomes the first goal. Their complexes have been studied by microanalysis, thermal, electrochemical and spectral (electronic, IR...

Kulkarni, A.; Patil, S.A.; Badami, P.S., 2010: DNA cleavage and in vitro antimicrobial studies of Co(II), Ni(II), and Cu(II) complexes with ONNO donor Schiff bases: synthesis, spectral characterization, and electrochemical studies. A series of Co(II), Ni(II), and Cu(II) complexes of the type ML.2H2O have been synthesized with Schiff bases derived from 8-formyl-7-hydroxy-4-methylcoumarin and o-phenylenediamine/ethylenediamine. The structure of the complexes has been proposed...

Kanchana Devi, A.; Ramesh, R., 2014: Synthesis, spectral and electrochemical studies of binuclear Ru(III) complexes containing dithiosemicarbazone ligand. Synthesis of several new octahedral binuclear ruthenium(III) complexes of the general composition [(EPh3)2(X)Ru-L-Ru(X)(EPh3)2] containing benzene dithiosemicarbazone ligands (where E=P or As; X=Cl or Br; L=binucleating ligands) is presented. All...

S.M.nivannan; R.P.abhakaran; K.P.B.lasubramanian; V.D.anabal; R.K.rvembu; V.C.innusamy; K.N.tarajan, 2007: Synthesis, spectral, electrochemical and catalytic studies of new Ru(III) tetradentate Schiff base complexes. The synthesis and characterization of several hexa-coordinated ruthenium(III) Schiff base complexes of the type [RuX(EPh3)(L)] (X = Cl or Br; E = P or As; L = dianion of the tetradentate Schiff base) are reported. IR, EPR, electronic spectra and c...

Anitha, N.; Balamurugan, R.; Palaniandavar, M., 2011: Spectral and electrochemical studies of bis(diimine)copper(II) complexes in anionic, cationic and nonionic micelles. The spectral and redox behavior of bis(diimine)copper(II) complexes, where diimine is bipyridine, 1,10-phenanthroline, 4-methyl-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 5-nitro-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 5,6-d...

Tarasevich M.R.; Bogdanovskaya V.A., 1976: Potentio dynamic and spectro electrochemical studies of the cytochrome c and some other iron containing complexes. Bioelectrochemistry & Bioenergetics 3(3/4): 589-595

Saad, F.A., 2014: Synthesis, spectral, electrochemical and X-ray single crystal studies on Ni(II) and Co(II) complexes derived from 1-benzoyl-3-(4-methylpyridin-2-yl) thiourea. 1-Benzoyl-3-(4-methylpyridin-2-yl) thiourea ligand was coordinated with Ni(II) and Co(II) perchlorate salts to isolate complexes. All the prepared compounds are deliberately investigated by all possible spectral tools. A comparative study for IR s...

Mohamed Subarkhan, M.; Ramesh, R., 2016: Binuclear ruthenium(III) bis(thiosemicarbazone) complexes: synthesis, spectral, electrochemical studies and catalytic oxidation of alcohol. A new series of binuclear ruthenium(III) thiosemicarbazone complexes of general formula [(EPh3)2(X)2Ru-L-Ru(X)2(EPh3)2] (where E=P or As; X=Cl or Br; L=NS chelating bis(thiosemicarbazone ligands) has been synthesized and characterized by analytica...

Abdel Aziz, A.A.; Elbadawy, H.A., 2015: Spectral, electrochemical, thermal, DNA binding ability, antioxidant and antibacterial studies of novel Ru(III) Schiff base complexes. Four new air stable low spin Ru(III) complexes of the type [Ru(L(1-4))(H2O)2]Cl have been synthesized, where L=dianion of the tetradentate Schiff base ligands namely N,N'bis(salicylaldehyde)4,5-dimethy-l,2-phenylendiammine (L(1)H2), N,N'...

Demirezen, N.; Tarınç, D.; Polat, D.; Ceşme, M.; Gölcü, Aşegül.; Tümer, M., 2012: Synthesis of trimethoprim metal complexes: Spectral, electrochemical, thermal, DNA-binding and surface morphology studies. Complexes of trimethoprim (TMP), with Cu(II), Zn(II), Pt(II), Ru(III) and Fe(III) have been synthesized. Then, these complexes have been characterized by spectroscopic techniques involving UV-vis, IR, mass and (1)H NMR. CHN elemental analysis, ele...