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Wyszukujesz frazę "unfolding" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Kinetic intermediates of unfolding of dimeric prostatic phosphatase
Autorzy:
Kuciel, Radosława
Mazurkiewicz, Aleksandra
Dudzik, Paulina
Powiązania:
https://bibliotekanauki.pl/articles/1041089.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
dimer
prostatic phosphatase
protein unfolding
Opis:
Kinetics of guanidine hydrochloride (GdnHCl)-induced unfolding of human prostatic acid phosphatase (hPAP), a homodimer of 50 kDa subunit molecular mass was investigated with enzyme activity measurements, capacity for binding an external hydrophobic probe, 1-anilinonaphtalene-8-sulfonate (ANS), accessibility of thiols to reaction with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) and 2-(4'-maleimidylanilino)naphthalene-6-sulfonate (MIANS) and ability to bind Congo red dye. Kinetic analysis was performed to describe a possible mechanism of hPAP unfolding and dissociation that leads to generation of an inactive monomeric intermediate that resembles, in solution of 1.25 M GdnHCl pH 7.5, at 20°C, in equilibrium, a molten globule state. The reaction of hPAP inactivation in 1.25 M GdnHCl followed first order kinetics with the reaction rate constant 0.0715 ± 0.0024 min-1 . The rate constants of similar range were found for the pseudo-first-order reactions of ANS and Congo red binding: 0.0366 ± 0.0018 min-1 and 0.0409 ± 0.0052 min-1, respectively. Free thiol groups, inaccessible in the native protein, were gradually becoming, with the progress of unfolding, exposed for the reactions with DTNB and MIANS, with the pseudo-first-order reaction rate constants 0.327 ± 0.014 min-1 and 0.216 ± 0.010 min-1, respectively. The data indicated that in the course of hPAP denaturation exposure of thiol groups to reagents took place faster than the enzyme inactivation and exposure of the protein hydrophobic surface. This suggested the existence of a catalytically active, partially unfolded, but probably dimeric kinetic intermediate in the process of hPAP unfolding. On the other hand, the protein inactivation was accompanied by exposure of a hydrophobic, ANS-binding surface, and with an increased capacity to bind Congo red. Together with previous studies these results suggest that the stability of the catalytically active conformation of the enzyme depends mainly on the dimeric structure of the native hPAP.
Źródło:
Acta Biochimica Polonica; 2007, 54, 2; 371-377
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Circular dichroism analysis for multidomain proteins: studies of the irreversible unfolding of Hepatitis C virus helicase
Autorzy:
Gozdek, Agnieszka
Stankiewicz-Drogoń, Anna
Poznański, Jarosław
Boguszewska-Chachulska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1040814.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Lumry-Eyring model
Hepatitis C virus
protein unfolding
circular dichroism
NS3 helicase
Opis:
The non-structural protein 3 (NS3) of Hepatitis C virus (HCV) is a bifunctional enzyme with RNA-dependent NTPase/RNA helicase and serine protease activities, and thus represents a promising target for anti-HCV therapy. These functions are performed by two distinct moieties; the N-terminal protease domain and the C-terminal helicase domain that further folds into three structural subdomains. To obtain lower molecular mass proteins suitable for nuclear magnetic resonance studies of helicase-inhibitor complexes, helicase domains 1, 2, and 1+2 devoid of a hydrophobic β-loop were overexpressed and purified. Circular dichroism studies were carried out to confirm the secondary structure content and to determine thermodynamic parameters describing the stability of the proteins. Both thermal and GuHCl-induced unfolding experiments confirmed the multidomain organization of the helicase. The unfolding transition observed for domain 1+2 was in agreement with the model of two well-resolved successive steps corresponding to the independent unfolding of domains 1 and 2, respectively. In the case of the full-length helicase, the presence of domain 3 remarkably changed the transition profile, leading to fast and irreversible transformation of partially unfolded protein.
Źródło:
Acta Biochimica Polonica; 2008, 55, 1; 57-66
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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