Comparison of intramolecular packing of a protein in native and ‘molten globule’ states

Damaschun, G.; Gernat, C.; Damaschun, Hilde; Bychkova, Valentina E.; Ptitsyn, Oleg B.

doi:10.1016/0141-8130(86)90031-0

Cited by 47 publications

(28 citation statements)

References 22 publications

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“…When transferred to conditions where they can refold completely, unfolded proteins tend to adopt compact, but nonnative, conformations that are in rapid equilibrium with each other and with more unfolded conformations (25,26); complete refolding occurs more slowly. These transient compact conformations appear (25)(26)(27)(28)(29)(30)(31) to be similar to the recently recognized "molten globule" state that is stable with some proteins under some conditions (32,33).…”

Section: Experimental Observations Of Protein Folding Transitionsmentioning

confidence: 84%

Toward a better understanding of protein folding pathways.

Creighton

1988

Proc. Natl. Acad. Sci. U.S.A.

123

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Experimental observations of how unfolded proteins refold to their native three-dimensional structures contrast with many popular theories of protein folding mechanisms. The available experimental evidence (ignoring slow cis-trans peptide bond isomerization) is largely consistent with the following general scheme: under folding conditions, unfolded protein molecules rapidly equilibrate between different conformations prior to complete refolding. This rapid prefolding equilibrium favors certain compact conformations that have somewhat lower free energies than the other unfolded conformations. Some of the favored conformations are important for productive folding. The rate-limiting step occurs late in the pathway and involves a high-energy, distorted form of the native conformation; there appears to be a single transition state through which essentially all molecules refold. Consequently, proteins are not assembled via a large number of independent pathways, nor is folding initiated by a nucleation event in the unfolded protein followed by rapid growth of the folded structure. The known folding pathways involving disulfide bond formation follow the same general principles. An exceptional folding mechanism for reduced ribonuclease A proposed by Scheraga et al. (Scheraga, H

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Section: Experimental Observations Of Protein Folding Transitionsmentioning

confidence: 84%

Toward a better understanding of protein folding pathways.

Creighton

1988

Proc. Natl. Acad. Sci. U.S.A.

123

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“…Experimentally this has been shown to be true using X-ray diffraction (Damaschun et al 1986), viscosity (Dolgikh et al 1981), gel exclusion chromatography ), light scattering (Gast et al Goto and Fink (1989) Goto and Fink (1989); Craig (1986) Robson and Pain (1976) Creighton and Pain (1980) Craig and Pain (1978) Thomas et al (1983) Mitcbinson and Pain (1985) Creighton and Pain ( 1986) and urea gradient gel electrophoresis (Creighton and Pain 1980). Different proteins exhibit stable intermediate states whose equivalent hydrodynamic radii of gyration or Stokes radii range from approximately one to 2 times those of the respective native states.…”

Section: The State Is Largely Globularmentioning

confidence: 99%

Molten globule intermediates and protein folding

1991

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The background to the concept of the term "molten globule" as a description of intermediates observed in the folding of globular proteins is discussed. These compact intermediates are characterised by certain properties including the presence of secondary structure and considerable conformational mobility compared to the native, functional state. Those intermediates that are thermodynamically stable under mild denaturing conditions have many features in common with the transient intermediates that accumulate significantly during the process of folding. Attention is drawn to cases where the two types are however distinguished on grounds of their Stokes radius, in which cases there is currently no direct evidence for the involvement of the stable intermediates on the folding pathway. Experimental evidence relating to the early stages in folding is reviewed and compared, highlighting the temporal relationship between general collapse of the polypeptide chain and the formation of secondary structure. The continued use of the term "molten globule" is recommended where the minimum essential structural criteria for this state are met.

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“…erogeneous, with defined secondary structure and the absence of rigid tertiary interactions (Dolgikh et al, 1981 ;Damaschun et al, 1986;Baum et al, 1989;Kuwajima, 1989;Ptitsyn et al, 1990;Ewbank & Creighton, 1991;Alexandrescu et al, 1993;Chyan et al, 1993;Peng & Kim, 1994;., 1995; Wu et al, 1995). Hydrogen exchange NMR studies of the acid denatured state of guinea pig and human a-LA'S have indicated that the molten globule state contains specific amides that are protected in the a-helical domain of the protein, suggesting that the a-domain forms the nucleus of the molten globule state and that the P-domain is essentially unfolded (Baum et al.…”

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confidence: 99%

Electrostatic interactions in the acid denaturation of α‐lactalbumin determined by nmr

Kim¹,

Baum²

1998

Protein Science

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Abstracta-Lactalbumin (a-LA) undergoes a pH-dependent unfolding from the native state to a partially unfolded state (the molten globule state). To understand the role of electrostatic interactions in protein denaturation, NMR and CD pH titration experiments are performed on guinea pig a-LA. Variation of pH over the range of 7.0 to 2.0 simultaneously leads to the acid denaturation of the protein and the titration of individual ionizable groups. The pH titrations are interpreted in the context of these coupled events, and indicate that acid denaturation in a-LA is a cooperative event that is triggered by the protonation of two ionizable residues. Our NMR results suggest that the critical electrostatic interactions that contribute to the denaturation of a-LA are concentrated in the calcium binding region of the protein.Keywords: chemical exchange; ionizable groups; NMR; pH titration; pK, values a-Lactalbumin (a-LA) offers an opportunity to study protein folding in the context of electrostatic interactions and metal binding (Hall & Campbell, 1986;McKenzie &White, 1991; Brew & Grobler, 1992;Sugai & Ikeguchi, 1994). Guinea pig a-LA contains 11 lysines, 4 histidines, 6 glutamic acids, and 16 aspartic acids that result in an isoelectric point of pH 4.65 (Fig. 1). a-LA isolated from milk contains an equimolar amount of bound calcium, which stabilizes the native structure, but other divalent metal ions including Mn2+, Zn2+, and Cu2+ can also bind to the protein (Kronman et al., 198 1;Rao & Brew, 1989). The structure of a-LA consists of two domains, an a-helical and a P-sheet domain (Acharya et al., 1989, 1991Pike et al., 1996), and a calcium binding loop in which two carbonyl groups corresponding to K79 and D84, and three carboxyl groups corresponding to D82, D87, and D88, act as ligands.a-LA undergoes a pH-dependent unfolding from the native state (N-state) to the acid denatured (A-state) or molten globule state (Kuwajima et al., Sommers & Kronman, 1980). The low pH form of a-LA is an ideal model system for studies of protein folding because the "molten globule" state that it adopts at low pH has been postulated to be analogous to an early intermediate on the protein folding pathway (Kuwajima et al., 1985;Ptitsyn et al., 1990). The low pH form of a-LA has been extensively studied by CD, NMR, and other spectroscopic and physicochemical methods (Dobson, 1994;Ptitsyn, 1995;Kuwajima, 1996)

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Comparison of intramolecular packing of a protein in native and ‘molten globule’ states

Cited by 47 publications

References 22 publications

Toward a better understanding of protein folding pathways.

Toward a better understanding of protein folding pathways.

Molten globule intermediates and protein folding

Electrostatic interactions in the acid denaturation of α‐lactalbumin determined by nmr

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