Relationship of protein thermostability to accessible surface area

Stellwagen, Earle; Wilgus, H. S.

doi:10.1038/275342a0

Cited by 78 publications

(38 citation statements)

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“…Recently, Stellwagen and Wilgus 31 ) have reported that the solventaccessible surface area was formed to result in a better correlation with protein thermostability. They have suggested that the increase of the internal area of proteins at the expense of the accessible surface area decreases their thermostability.…”

Section: Discussionmentioning

confidence: 99%

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Yamagishi

Miyakawa

Noda

et al. 1983

Agricultural and Biological Chemistry

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Heating of 7S globulin alone did not cause precipitation, but addition of lIS globulin to the system did. Gel filtration and ion exchange chromatography, followed by electrophoresis of the precipitate and supernatant, suggested an interaction through disulfide bonding between the 7S and 11 S globulin subunits. )"'he basic and f3 subunits tended to be located in the precipitate by interaction through a secondary force on heating. On the other hand, the acidic and (X(X' subunits tended to be located in the supernatant by interaction through disulfide bonding on heating.Using the predictive parameter of amino acids, each macroscopic parameter of the soybean globulin subunits was calculated on the basis of their amino acid composition and a relationship with their behavior on heating is discussed. 1229Heating contributes to the orientation of texture in many food systems.! --4) For example, .precipitation and heat-setting in hot water form the filament in a spinning process,5) and when making tofu, a traditional Japanese food, the heating of soybean milk plays a major role in forming its characteristic gel, while heating tofu to high temperature produces "aburage" (fried tofu) as textured proteins. 6 ) To acquire a basic knowledge about the thermal aggregation behaviour of food proteins, soybean lIS globulin has been used as a model for the examination of thermal aggregation, 7 --9) because it contains the sulfbydryl and disulfide residues, which playa major role in the formation of texture. In a food system, not only lIS globulin, but also 7S globulin must contribute to the orientation of texture by interacting with each other on heating. Thus, as a model system for heating food proteins, a mixture of purified 7S and lIS globulins was settled upon for this study.In this present investigation, we have studied heat-aggregated and -dissociated products by means of gel filtration, ion exchange chromatography and electrophoresis. MATERIALS AND METHODSMaterials. Soybean, cv. Raiden, was used throughout this work. Defatted meal was prepared from the soybean by grinding, defatting with n-hexane and removing the solvent at room temperature. All reagents were of the highest grade. Sepharose CL-6B and CL-2B, and DEAESephadex A-50 were obtained from Pharmacia Fine Chemicals.Preparation of 78 and 118 globulins. Thanh's crude 7S globulin 1 0) was prepared and purified by the method described in the previous paper. 11) The concentration of 7S globulin in the standard buffer was determined spectrophotometrically, using the value E~r~= 5.74. 12 ) Purified 11 S globulin was prepared by the method described in the previous paper. 7 ) Each protein was adjusted to a 1%concentration.Procedure for heat treatment. An equal mixture solution of 1% 7S and lIS globulins was used for heat treatment. Heating studies and experiments with 0.02 M Nethylmaleimide (NEM) were carried out by the method described in the previous paper. 9 ) The heated solutions were centrifuged for 10 min at 5000 rpm if a precipitate was present.Electrophoresis. Acetic ...

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Section: Discussionmentioning

confidence: 99%

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Yamagishi

Miyakawa

Noda

et al. 1983

Agricultural and Biological Chemistry

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“…Interaction between NCS protein and NCS-C(b) is suggested to be hydrophobic by structural simulation [45]. The specific NCS-C(b) binding that reduces the solvent exposure near the binding cleft and protects the internal hydrophobic core of the protein might be crucial for the protein stability [46]. Chemically, it remains obscure why the NCS-C that bears an epoxide moiety is more stable in acids than in bases.…”

Section: Protein and Chromophore Conjugation Ensures Functional Mutuamentioning

confidence: 99%

Is association of labile enediyne chromophore a mutually assured protection for carrier protein?

Jayachithra¹,

Hariharan²,

Kumar³

et al. 2008

Analytical Biochemistry

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Most conjugate proteins undergo both conformational and stability changes on ligand removal. When architecture remains unchanged in the protein holo and apo forms, it is uncertain whether the protein stability also remains unaltered in both of the forms. Neocarzinostatin (NCS), a chromoprotein possessing a potent enediyne chromophore stands for such an instance. Protein-chromophore interaction has not been thoroughly explored previously due to a lack of strategies to independently and simultaneously monitor changes in the NCS conjugates. Here we report a method by which one can detect the signal exclusively from only one of the NCS conjugates without the spectral interference from the other. Stability of the NCS protein is significantly correlated to the proteinbound chromophore, irrespective of denaturation by heat, pH, urea, or ethanol. Despite the similarity in protein backbone conformation, protein stability of the NCS holo form diminishes and equalizes to that of the apo form when the chromophore is released and degraded. Although the enediyne chromophore is highly unstable, it intriguingly protects the protein by which it is protected. Significant mutual reliance between the carrier protein and its naturally associated ligand unveils important information on the NCS drug stability. KeywordsEnediyne; Neocarzinostatin; Chromophore; Ligand binding; Holoprotein; Protein stability Recently, much attention has been focused on the protein-ligand conjugation. Most conjugate proteins undergo changes in their conformation and subsequently, in stability on ligand removal [1][2][3]. For example, binding of heme to cytochrome changes the protein conformation and consequently, increases the protein stability [4]. It is rather uncommon for conjugate proteins to adopt a like conformation with or without the ligand. This includes azurin (β protein with a copper ion), flavodoxin (α/β protein with a flavin mononucleotide) [5], neocarzinostatin (NCS, 1 β protein with an enediyne chromophore) [6,7] and so on. In spite of structural similarity, the holo form of azurin is more stable than its apo form [8]. The flavodoxin holo form, in contrast, has little changes in either conformation or stability on its cofactor removal *Corresponding author. Fax: +886 4 22862547. E-mail address: chdhchin@dragon.nchu.edu.tw (D.-H. Chin). 1 Abbreviations used: NCS, neocarzinostatin; holoNCS, neocarzinostatin chromoprotein conjugate complex; apoNCS, apoprotein of neocarzinostatin; NCS-C, neocarzinostatin chromophore; NCS-C(b), protein-bound neocarzinostatin chromophore; CD, circular dichroism; HPLC, high-performance liquid chromatography; EtBr, ethidium bromide; NOESY, nuclear Overhauser effect spectroscopy; NMR, nuclear magnetic resonance; T m , temperature at which half of the protein is unfolded; T r , temperature at which half of the NCS-C(b) is released from NCS complex; C m , concentration of denaturant at which half of the protein is unfolded; C r , concentration of denaturant at which half of the NCS-C(b) is released from NCS com...

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“…A remarkable increase in ovalbumin aggregates was apparent near the melting point (76°C) for thermal denaturation. 8 ) The molecualr. weight of ovalbumin aggregates was determined by using the low angle laser light scattering technique in com- bination with high performance liquid chromatography.…”

Section: Methodsmentioning

confidence: 99%

Determination of Molecular Weight of Soluble Ovalbumin Aggregates during Heat Denaturation Using Low Angle Laser Light Scattering Technique

Kato

NAGASE

Matsudomi

et al. 1983

Agricultural and Biological Chemistry

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Relationship of protein thermostability to accessible surface area

Cited by 78 publications

References 10 publications

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Isolation and Electrophoretic Analysis of Heat-induced Products of Mixed Soybean 7S and 11S Globulins

Is association of labile enediyne chromophore a mutually assured protection for carrier protein?

Determination of Molecular Weight of Soluble Ovalbumin Aggregates during Heat Denaturation Using Low Angle Laser Light Scattering Technique

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