Study of the ?molten globule? intermediate state in protein folding by a hydrophobic fluorescent probe

Biopolymers ◽  
1991 ◽  
Vol 31 (1) ◽  
pp. 119-128 ◽  
Author(s):  
G. V. Semisotnov ◽  
N. A. Rodionova ◽  
O. I. Razgulyaev ◽  
V. N. Uversky ◽  
A. F. Gripas' ◽  
...  
Keyword(s):  
Protein Folding ◽  
Fluorescent Probe ◽  
Intermediate State ◽  
Molten Globule

scholarly journals Loops linking secondary structure elements affect the stability of molten globule intermediate state of apomyoglobin

2019 ◽  
Author(s):  
M.A. Majorina ◽  
B.S. Melnik
Keyword(s):  
Protein Folding ◽  
Secondary Structure ◽  
Rate Constant ◽  
Intermediate State ◽  
Molten Globule ◽  
Protein Secondary Structure ◽  
Free Energies ◽  
Real Effect ◽  
Unfolded State ◽  
The Stability

AbstractApomyoglobin is a protein widely used as a model for studying globular protein folding. This work aimed to test the hypothesis on influence of rigidity and length of loops linking protein secondary structure elements on the stability of molten globule intermediate state. For this purpose, we studied folding/unfolding of mutant apomyoglobin forms with substitutions of proline residues to glycine and with loops elongated by three and six glycine residues. For all the protein forms, denaturation/renaturation kinetic curves at different urea concentrations were obtained, folding/unfolding constants were calculated and dependencies of rate constant logarithms on urea concentrations were plotted. All the data gave an opportunity to calculate free energies of different apomyoglobin states. As a result, the mutations in apomyoglobin loops were demonstrated to have a real effect on intermediate state stability compared to unfolded state.

Models of cooperativity in protein folding

1995 ◽  
Vol 348 (1323) ◽  
pp. 61-70 ◽  
Keyword(s):  
Protein Folding ◽  
Molten Globule ◽  
Core Collapse ◽  
Hydrophobic Core ◽  
Model Studies ◽  
Helix Formation ◽  
Collapse Model ◽  
Folding Pathways ◽  
State Behaviour ◽  
Denatured States

What is the basis for the two-state cooperativity of protein folding? Since the 1950s, three main models have been put forward. 1. In ‘helix-coil’ theory, cooperativity is due to local interactions among near neighbours in the sequence. Helix-coil cooperativity is probably not the principal basis for the folding of globular proteins because it is not two-state, the forces are weak, it does not account for sheet proteins, and there is no evidence that helix formation precedes the formation of a hydrophobic core in the folding pathways. 2. In the ‘sidechain packing’ model, cooperativity is attributed to the jigsaw-puzzle-like complementary fits of sidechains. This too is probably not the basis of folding cooperativity because exact models and experiments on homopolymers with sidechains give no evidence that sidechain freezing is two-state, sidechain complementarities in proteins are only weak trends, and the molten globule model predicted by this model is far more native-like than experiments indicate. 3. In the ‘hydrophobic core collapse’ model, cooperativity is due to the assembly of non-polar residues into a good core. Exact model studies show that this model gives two-state behaviour for some sequences of hydrophobic and polar monomers. It is based on strong forces. There is considerable experimental evidence for the kinetics this model predicts: the development of hydrophobic clusters and cores is concurrent with secondary structure formation. It predicts compact denatured states with sizes and degrees of disorder that are in reasonable agreement with experiments.

scholarly journals SUN-219 Electron Transport Chain Complex 2 in Mitochondrial Pregnenolone Synthesis

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Himangshu S Bose ◽  
Brendan Marshall ◽  
Dilip Debnath ◽  
Elizabeth W Perry ◽  
Randy M Whittal
Keyword(s):  
Electron Transport ◽  
Intermediate State ◽  
Electron Transport Chain ◽  
Molten Globule ◽  
Tca Cycle ◽  
Steroid Synthesis ◽  
Aberrant Expression ◽  
Complex Ii ◽  
The Tca Cycle ◽  
Transport Chain

Abstract The mitochondrial P450 family of enzymes (SCC), which require the electron transport chain (ETC) complexes III, IV and V, initiate steroidogenesis by cleaving the sidechain of cholesterol to synthesize steroid hormones, an essential component for mammalian survival. SCC is required for full-term gestation, and aberrant expression may cause pseudohermaphroditism, breast cancer or polycystic ovary syndrome. Complex II or succinate dehydrogenase (quinone) is shared with the TCA cycle and has no proton pumping capacity and no known role in steroid synthesis. We now show that succinate is an intermediate metabolite in the TCA cycle and plays a central role physiologically. Specifically, complex II is required for SCC activation, where the proton pump facilitates an active intermediate state conformation at the matrix, so that in the presence of succinate, ATP can add phosphate. A longer intermediate equilibrium state generates a transient stabilization to enhance the binding of phosphate anions in the presence of succinate anions, resulting in higher enthalpy and activity. An inhibition of the processing at the intermediate state stops phosphate addition and activity. We further describe that phosphate circulation brings the molten globule, an intermediate, to an active folded state. This is the first report showing that an intermediate state activated by succinate facilitates ETC complex II interaction with complexes III and IV for metabolism.

scholarly journals Loops linking secondary structure elements affect the stability of the molten globule intermediate state of apomyoglobin

FEBS Letters ◽  
2020 ◽  
Vol 594 (20) ◽  
pp. 3293-3304
Author(s):  
Maria A. Majorina ◽  
Vitaly A. Balobanov ◽  
Vladimir N Uversky ◽  
Bogdan S. Melnik
Keyword(s):  
Secondary Structure ◽  
Intermediate State ◽  
Molten Globule ◽  
The Stability

Molten globule intermediates and protein folding

1991 ◽  
Vol 19 (5) ◽  
Author(s):  
H. Christensen ◽  
R.H. Pain
Keyword(s):  
Protein Folding ◽  
Molten Globule

scholarly journals The molten globule intermediate of apomyoglobin and the process of protein folding

1993 ◽  
Vol 2 (6) ◽  
pp. 869-876 ◽  
Author(s):  
Doug Barrick ◽  
Robert L. Baldwin
Keyword(s):  
Protein Folding ◽  
Molten Globule

Kinetic and equilibrium folding intermediates

1995 ◽  
Vol 348 (1323) ◽  
pp. 35-41 ◽  
Keyword(s):  
Protein Folding ◽  
Molten Globule ◽  
Low Dielectric Constant ◽  
The Novel ◽  
Folding Intermediate ◽  
Molten Globule State ◽  
Folding Intermediates ◽  
First Order ◽  
Low Dielectric ◽  
First Order Phase

Our recent experiments on the molten globule state and other protein folding intermediates lead to following conclusions: (i) the molten globule is separated by intramolecular first-order phase transitions from the native and unfolded states and therefore is a specific thermodynamic state of protein molecules; (ii) the novel equilibrium folding intermediate (the ‘pre-molten globule’ state) exists which can be similar to the ‘burst’ kinetic intermediate of protein folding; (iii) proteins denature and release their non-polar ligands at moderately low pH and moderately low dielectric constant, i.e. under conditions which may be related to those near membranes.

Cold Denaturation of the Molten Globule States of Apomyoglobin and a Profile for Protein Folding

Biochemistry ◽  
1994 ◽  
Vol 33 (16) ◽  
pp. 4903-4909 ◽  
Author(s):  
Ichiro Nishii ◽  
Mikio Kataoka ◽  
Fumio Tokunaga ◽  
Yuji Goto
Keyword(s):  
Protein Folding ◽  
Molten Globule ◽  
Cold Denaturation

Characterization of a Urea Induced Molten Globule Intermediate State of Glutaminyl-tRNA Synthetase from Escherichia coli

Biochemistry ◽  
1995 ◽  
Vol 34 (15) ◽  
pp. 5242-5247 ◽  
Author(s):  
Biplab K. Das ◽  
Tista Battacharyya ◽  
Siddhartha Roy
Keyword(s):  
Escherichia Coli ◽  
Intermediate State ◽  
Molten Globule ◽  
Trna Synthetase
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