scholarly journals Conformational changes induced by polyanions in haemoglobin from the dromedary (Camelus dromedarius) Role of chloride ions

1986 ◽  
Vol 240 (2) ◽  
pp. 613-616 ◽  
Author(s):  
R Santucci ◽  
G Amiconi ◽  
F Ascoli ◽  
M Brunori
Keyword(s):  
Conformational Changes ◽  
Functional Data ◽  
Tertiary Structure ◽  
Chloride Ions ◽  
Camelus Dromedarius ◽  
Dextran Sulphate ◽  
Inositol Hexakisphosphate ◽  
Midpoint Potential ◽  
Physiological Value

The role of chloride ions in modulating polyanion-induced conformational changes in haemoglobin from the dromedary (Camelus dromedarius) has been investigated. The results obtained have shown that: in the ferric derivative at pH 6.5 the effect of single polyanion (dextran sulphate and inositol hexakisphosphate) on the conformation is essentially local, thus involving only the tertiary structure of the protein; the presence of chloride ions at a concentration close to the physiological value (i.e. 150 mM) is essential to induce quaternary conformational changes in the polyanion-ferric protein system; comparison between structural and functional data correlates polyanion-induced tertiary conformational changes with changes in the value of midpoint potential, E'0, and quaternary changes with co-operativity.

scholarly journals Conformational changes induced by polyanions in haemoglobin from Camelus dromedarius. Circular-dichroism study on the oxy derivative

1985 ◽  
Vol 231 (3) ◽  
pp. 793-796 ◽  
Author(s):  
R Santucci ◽  
F Ascoli ◽  
G Amiconi ◽  
A Bertollini ◽  
M Brunori
Keyword(s):  
Functional Properties ◽  
Conformational Changes ◽  
Direct Evidence ◽  
Tertiary Structure ◽  
Camelus Dromedarius ◽  
Local Change ◽  
Inositol Hexakisphosphate ◽  
Human Haemoglobin ◽  
Circular Dichroïsm ◽  
O2 Binding

The c.d. spectrum of oxyhaemoglobin from Camelus dromedarius is significantly affected by the presence of inositol hexakisphosphate. Correlation with O2-binding measurements shows that these dichroic changes parallel the functional properties of the protein. The optical modifications suggest that, in contrast with human haemoglobin, the conformational changes induced by inositol hexakisphosphate on dromedary oxyhaemoglobin are mainly attributable to a local change of the tertiary structure reminiscent of that of the deoxy derivative, the quaternary conformation seeming to be almost unaffected. The results provide direct evidence of the existence on the protein of two distinct sites for polyanions.

scholarly journals Conformational changes induced by polyanions in haemoglobin from Camelus dromedarius. Studies on the ferric derivatives

1986 ◽  
Vol 235 (3) ◽  
pp. 791-795 ◽  
Author(s):  
R Santucci ◽  
F Ascoli ◽  
G Amiconi ◽  
M Brunori
Keyword(s):  
Spin State ◽  
Conformational Changes ◽  
Binding Sites ◽  
Camelus Dromedarius ◽  
Inositol Hexakisphosphate ◽  
Protein Conformational Changes ◽  
T State ◽  
Redox Equilibria ◽  
Derivatives Of

The effect of inositol hexakisphosphate on the redox equilibria and on the c.d. spectra of ferric derivatives of haemoglobin from Camelus dromedarius has shown that: two distinct functionally relevant binding sites for polyanions are present on the protein; conformational changes promoted by inositol hexakisphosphate are largely dependent on spin state of the iron; tertiary and quaternary changes are not necessarily linked; structures induced by polyanions can be mixed forms that are neither T-state nor R-state.

Role of spectrin in membrane fusion and in shape change of human erythrocyte ghost

1978 ◽  
Vol 36 (2) ◽  
pp. 328-329
Author(s):  
Hideo Hayashi ◽  
Yoshikazu Hirai ◽  
John T. Penniston
Keyword(s):  
Conformational Changes ◽  
Human Erythrocyte ◽  
Shape Change ◽  
Membrane Surface ◽  
Slight Modification ◽  
Active Role ◽  
Main Role ◽  
Bank Blood ◽  
Human Erythrocyte Ghost

Spectrin is a membrane associated protein most of which properties have been tentatively elucidated. A main role of the protein has been assumed to give a supporting structure to inside of the membrane. As reported previously, however, the isolated spectrin molecule underwent self assemble to form such as fibrous, meshwork, dispersed or aggregated arrangements depending upon the buffer suspended and was suggested to play an active role in the membrane conformational changes. In this study, the role of spectrin and actin was examined in terms of the molecular arrangements on the erythrocyte membrane surface with correlation to the functional states of the ghosts.Human erythrocyte ghosts were prepared from either freshly drawn or stocked bank blood by the method of Dodge et al with a slight modification as described before. Anti-spectrin antibody was raised against rabbit by injection of purified spectrin and partially purified.

scholarly journals Role of conformational heterogeneity in ligand recognition by viral RNA molecules

2021 ◽  
Author(s):  
Lev Levintov ◽  
Harish Vashisth
Keyword(s):  
Conformational Changes ◽  
Ribonucleic Acid ◽  
Viral Rna ◽  
Ligand Recognition ◽  
Conformational Heterogeneity ◽  
Rna Molecules ◽  
Environmental Stimuli

Ribonucleic acid (RNA) molecules are known to undergo conformational changes in response to various environmental stimuli including temperature, pH, and ligands. In particular, viral RNA molecules are a key example...

scholarly journals Role of Autochthonous Filamentous Fungi in Bioremediation of a Soil Historically Contaminated with Aromatic Hydrocarbons

2006 ◽  
Vol 72 (1) ◽  
pp. 28-36 ◽  
Author(s):  
A. D'Annibale ◽  
F. Rosetto ◽  
V. Leonardi ◽  
F. Federici ◽  
M. Petruccioli
Keyword(s):  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Chloride Ions ◽  
Lepidium Sativum ◽  
Fungal Colonization ◽  
Soil Toxicity ◽  
Germination Test ◽  
Lignin Peroxidases ◽  
Ph Conditions

ABSTRACT Nine fungal strains isolated from an aged and heavily contaminated soil were identified and screened to assess their degradative potential. Among them, Allescheriella sp. strain DABAC 1, Stachybotrys sp. strain DABAC 3, and Phlebia sp. strain DABAC 9 were selected for remediation trials on the basis of Poly R-478 decolorization associated with lignin-modifying enzyme (LME) production. These autochthonous fungi were tested for the abilities to grow under nonsterile conditions and to degrade various aromatic hydrocarbons in the same contaminated soil. After 30 days, fungal colonization was clearly visible and was confirmed by ergosterol determination. In spite of subalkaline pH conditions and the presence of heavy metals, the autochthonous fungi produced laccase and Mn and lignin peroxidases. No LME activities were detected in control microcosms. All of the isolates led to a marked removal of naphthalene, dichloroaniline isomers, o-hydroxybiphenyl, and 1,1′-binaphthalene. Stachybotrys sp. strain DABAC 3 was the most effective isolate due to its ability to partially deplete the predominant contaminants 9,10-anthracenedione and 7H-benz[DE]anthracen-7-one. A release of chloride ions was observed in soil treated with either Allescheriella sp. strain DABAC 1 or Stachybotrys sp. strain DABAC 3, suggesting the occurrence of oxidative dehalogenation. The autochthonous fungi led to a significant decrease in soil toxicity, as assessed by both the Lepidium sativum L. germination test and the Collembola mortality test.

Conformational Changes of Yeast Plasma Membrane H+-ATPase during Activation by Glucose:  Role of Threonine-912 in the Carboxy-Terminal Tail†

Biochemistry ◽  
2005 ◽  
Vol 44 (50) ◽  
pp. 16624-16632 ◽  
Author(s):  
Silvia Lecchi ◽  
Kenneth E. Allen ◽  
Juan Pablo Pardo ◽  
A. Brett Mason ◽  
Carolyn W. Slayman
Keyword(s):  
Plasma Membrane ◽  
Conformational Changes ◽  
Yeast Plasma Membrane ◽  
Carboxy Terminal

scholarly journals The effects of Ca2+ and Cd2+ on the secondary and tertiary structure of bovine testis calmodulin. A circular-dichroism study

1986 ◽  
Vol 238 (2) ◽  
pp. 485-490 ◽  
Author(s):  
S R Martin ◽  
P M Bayley
Keyword(s):  
Circular Dichroism ◽  
Conformational Changes ◽  
Metal Ion ◽  
Tertiary Structure ◽  
Thermal Unfolding ◽  
Apparent Effect ◽  
Thermally Induced ◽  
Circular Dichroïsm ◽  
Secondary And Tertiary Structure

Near-u.v. and far-u.v. c.d. spectra of bovine testis calmodulin and its tryptic fragments (TR1C, N-terminal half, residues 1-77, and TR2C, C-terminal half, residues 78-148) were recorded in metal-ion-free buffer and in the presence of saturating concentrations of Ca2+ or Cd2+ under a range of different solvent conditions. The results show the following: if there is any interaction between the N-terminal and C-terminal halves of calmodulin, it has not apparent effect on the secondary or tertiary structure of either half; the conformational changes induced by Ca2+ or Cd2+ are substantially greater in TR2C than they are in TR1C; the presence of Ca2+ or Cd2+ confers considerable stability with respect to urea-induced denaturation, both for the whole molecule and for either of the tryptic fragments; a thermally induced transition occurs in whole calmodulin at temperatures substantially below the temperature of major thermal unfolding, both in the presence and in the absence of added metal ion; the effects of Cd2+ are identical with those of Ca2+ under all conditions studied.

The Functional Role of the Conformational Changes in Arrestin Upon Activation

2017 ◽  
pp. 219-234
Author(s):  
Zhao Yang ◽  
Fan Yang ◽  
Anthony Nguen ◽  
Chuan Liu ◽  
Amy Lin ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Functional Role
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