Metal ion coordination in ‘R’ and ‘T’ state hybrid hemoglobins as revealed by optical, EPR and sulphhydryl reactivity studies

نویسندگان

  • S RAMASAMY
  • SWARNALATHA VENKATESHRAO
  • J M RIFKIND
  • P T MANOHARAN
چکیده

The sulphhydryl environment in various mixed-metal hybrid hemoglobins, viz. α2(Cu)β2(FeCO), α2(FeCO)-β2(Cu), α2(Cu)-β2(Ni), α2(Ni)-β2(Cu), was studied by reacting them with the sulphhydryl reagent, 4,4′-dithiodipyridine (4-PDS). The reactivity was compared with that of HbCO, NiHb and CuHb. It is found that there exists a correlation between conformational change and metal ion environment, not only at the extreme R and T states but also the intermediate conformations. EPR examinations of these hybrids show that both in R state-[Cu(II)-Fe(II)] and T state-[Cu(II)-Ni(II)] hybrids at neutral pH and in the absence of IHP, CuPPIX, irrespective of the subunit in which it is present, has a mixed-metal ion environment: Species 1, a five-coordinated Cu complex with strong proximal histidine bond and species 2, a four-coordinated complex without any covalent linkage with Nε F8-histidine.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Coordination and Siting of Cu+ Ion Adsorbed into Silicalite-2 Porous Structure: A Density Functional Theory Study

Coordination of Cu+ ions adsorbed on plausible sites of a silicalite-2 lattice has been investigated computationally via hybrid density functional theory method at the B3LYP/6-311+G* and B3LYP/Def2-TZVP levels of theory using molecular models of the active site. The symmetrical coordination of Cu+ ions to almost five oxygen atoms of the all-silica framework in six-membered ring (6MR) sites of t...

متن کامل

The Effect of Heat Treatment on the Microstructure and Mechanical Properties of Al/Al3Zr + Al3Ti In-situ Hybrid Composite Fabricated by Friction Stir Processing

In this research, an in-situ hybrid composite reinforced by Al3Zr and Al3Ti aluminide particles was fabricated by friction stir processing (FSP). The base metal was in the form of a rolled Al 3003-H14 alloy sheet, and zirconium and titanium metal powders were used as the reinforcements. Six passes of FSP were applied. Tensile strength and hardness of the base metal, as well as FSPed samples bef...

متن کامل

Studies on cobalt myoglobins and hemoglobins. Electron paramagnetic resonance investigation of iron-cobalt hybrid hemoglobins and its implication for the heme-heme interaction and for the alkaline Bohr effect.

An artificial hybrid hemoglobin cu(Co)P(Fe), the (Y and p subunits of which contain cobaltous protoporphyrin IX and ferrous protoporphyrin IX, respectively, and its complementary hybrid cu(Fe)P(Co), were prepared and examined by electron paramagnetic resonance spectroscopy. The fully oxy EPR spectra of cu(Co)p(Fe) and cu(Fe)P(Co) differ in their hyperfine splitting from each other, showing diff...

متن کامل

Multifrequency EPR studies of manganese catalases provide a complete description of proteinaceous nitrogen coordination.

Pulse electron paramagnetic resonance (EPR) spectroscopy is employed at two very different excitation frequencies, 9.77 and 30.67 GHz, in the study of the nitrogen coordination environment of the Mn(III)Mn(IV) state of the dimanganese-containing catalases from Lactobacillus plantarum and Thermus thermophilus. Consistent with previous studies, the lower-frequency results reveal one unique histid...

متن کامل

Plumbum(II) and Zinc(II) Complexes with 5-Chlorosalicylic Acid: Structure and Propertie

Abstract: Two new transition metal complexes, containing the acidic ligand 5-chlorosalicylic acid (H2L5), and 1,10-phenanthroline(phen) and 1,3-Di(4-pyridyl)propane (bpp) as secondary ligands are reported. They are formulated as {[Pb(HL5)2(phen)(H2O)]·H2O}n(1), [Zn2(HL5)4(bpp)2]n(2). All the complexes are characterized by single-crystal X-ray diffractions. Compoud 1 crystallizes in the triclini...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2005