Nucleotide binding to actin. Cation dependence of nucleotide dissociation and exchange rates.

Kinosian, Henry J.; Selden, Lynn A.; Estes, James E.; Gershman, Lewis C.

doi:10.1016/s0021-9258(18)52929-x

Cited by 89 publications

(52 citation statements)

References 38 publications

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“…In our experiments the replacement of Ca# + with Mg# + was effected by a short treatment of Ca-ATP-G-actin with EGTA\MgCl # , whereas the procedure used by Kim et al [43] involved polymerization of the Mg-ADP form followed by its depolymerization (through dialysis) in the presence of MgATP. In view of slow but significant hydrolysis of ATP on Mg-G-actin [26,38,44] and of the relatively high affinity of MgADP for actin [45], this latter (prolonged) procedure is likely to lead to a mixture of Mg-ATP-G-actin and Mg-ADP-G-actin.…”

Section: Discussionmentioning

confidence: 99%

Structural changes in subdomain 2 of G-actin observed by fluorescence spectroscopy

Moraczewska

Strzelecka‐Gołaszewska

Moens

et al. 1996

Biochemical Journal

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The influence of DNase I binding to Ca-ATP-G-actin and of Ca2+/Mg2+ and ATP/ADP exchange on the conformation of G-actin were investigated by measuring the fluorescence of dansyl cadaverine (DC) conjugated to Gln41 in subdomain 2 of the protein. Fluorescence resonance energy transfer (FRET) between this probe and N-[4-(dimethylamino)-3,5-dinitrophenyl]maleimide (DDPM) attached to Cys374 in subdomain 1 was also measured. Contrary to an earlier report [dos Remedios, Kiessling and Hambly (1994) in Synchrotron Radiation in the Biosciences (Chance, B., Deisenhofer, J., Ebashi, S., Goodhead, D. T., Helliwell, J. R., Huxley, H. E., Iizuka, T., Kirz, J., Mitsui, T., Rubenstein, E. et al., eds.), pp. 418-425, Oxford University Press, Oxford], the distance between these probes did not change significantly when DNase I was bound to actin. A small but reproducible increase in the quantum yield and a blue shift of the DC fluorescence maximum were observed when bound Ca2+ was replaced by Mg2+. A large increase (about 70%) in the quantum yield and an approx. 12 nm blue shift of the emission spectrum occurred when ATP in Mg-G-actin was replaced by ADP. These changes were not accompanied by any significant change in the FRET distance between the dansyl donor and DDPM acceptor probes. A substantial change in the fluorescence of DC-actin was observed after proteolytic removal of the last three residues of actin, in accordance with earlier evidence suggesting that there is a conformational coupling between subdomain 2 and the C-terminal segment in subdomain 1 of actin. The results are discussed in relation to recently published data obtained with another fluorescent probe and to earlier observations based on limited cleavage using proteolytic enzymes.

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Section: Discussionmentioning

confidence: 99%

Structural changes in subdomain 2 of G-actin observed by fluorescence spectroscopy

Moraczewska

Strzelecka‐Gołaszewska

Moens

et al. 1996

Biochemical Journal

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“…Release of these moieties under physiological conditions leads to spontaneous unfolding of the protein (Lehrer & Kerwar 1972;Nagy & Strzelecka-Golaszewska 1972;Kuznetsova et al 1988). There has been extensive study into the mechanism of nucleotide and metal ion loss/exchange (Nowak et al 1988;Gershman et al 1991;Estes et al 1992;Kinosian et al 1993;McCormack et al 2001a), to allow further understanding of both the process of actin polymerization and the unfolding pathway (Bertazzon et al 1990;Schuler et al 2000;Kuznetsova et al 2002;Turoverov et al 2002;Altschuler et al 2005;Povarova et al 2007). Actin unfolding is generally thought to occur via the sequential loss of cation and nucleotide to produce an unfolded intermediate I 2 , which in turn spontaneously unfolds further to form an aggregationprone intermediate I 3 (Altschuler et al 2005).…”

Section: The Folding and Unfolding Pathways Of Actinmentioning

confidence: 99%

“…The I 1 $ATP $$% !$$ I 2 C ATP equilibrium is rapidly established relative to the other steps (Kinosian et al 1993), and based on this assumption our stopped-flow fluorescence study has verified the reaction scheme and calculated the kinetic parameters (Altschuler et al 2005). I 2 can be stabilized with respect to further unfolding towards I 3 by high concentrations of sucrose (Kasai et al 1965;De La Cruz & Pollard 1995) or glycerol (Altschuler 2006 (Rohman 1999) and spontaneously binds nucleotide and cation, stabilizing actin in a conformational ensemble referred to as the 'native platform' (green shaded area).…”

Section: The Folding and Unfolding Pathways Of Actinmentioning

confidence: 99%

Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

Altschuler

Willison

2008

J. R. Soc. Interface.

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A free-energy-based approach is used to describe the mechanism through which chaperonincontaining TCP-1 (CCT) folds the filament-forming cytoskeletal protein actin, which is one of its primary substrates. The experimental observations on the actin folding and unfolding pathways are collated and then re-examined from this perspective, allowing us to determine the position of the CCT intervention on the actin free-energy folding landscape. The essential role for CCT in actin folding is to provide a free-energy contribution from its ATP cycle, which drives actin to fold from a stable, trapped intermediate I 3 , to a less stable but now productive folding intermediate I 2 . We develop two hypothetical mechanisms for actin folding founded upon concepts established for the bacterial type I chaperonin GroEL and extend them to the much more complex CCT system of eukaryotes. A new model is presented in which CCT facilitates free-energy transfer through direct coupling of the nucleotide hydrolysis cycle to the phases of actin substrate maturation.

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“…The exchange rates of ATP for both Mg 2+ -and Ca 2+ -G-actin are even more different (5 3 10 À4 and 1.5 3 10 À2 , respectively) (Sheterline and Sparrow, 1994). As ATP exchange rates are tightly connected to free metal concentrations, the metal-ion exchange rate would be a limiting factor for nucleotide exchange (Kinosian et al, 1993). Even if we attribute all of the metal exchange rate difference to coordination states, still there is a difference in ATP exchange rates.…”

Section: Actin Model Consistency With Nucleotide and Metal-ion Exchange Ratesmentioning

confidence: 99%

Biochemical Implications of a Three-Dimensional Model of Monomeric Actin Bound to Magnesium-Chelated ATP

2007

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Actin structure is of intense interest in biology due to its importance in cell function and motility mediated by the spatial and temporal regulation of actin monomer-filament interconversions in a wide range of developmental and disease states. Despite this interest, the structure of many functionally important actin forms has eluded high-resolution analysis. Due to the propensity of actin monomers to assemble into filaments structural analysis of Mg-bound actin monomers has proven difficult, whereas high-resolution structures of actin with a diverse array of ligands that preclude polymerization have been quite successful. In this work, we provide a high-resolution structural model of the Mg-ATP-actin monomer using a combination of computational methods and experimental footprinting data that we have previously published. The key conclusion of this study is that the structure of the nucleotide binding cleft defined by subdomains 2 and 4 is essentially closed, with specific contacts between two subdomains predicted by the data.

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Nucleotide binding to actin. Cation dependence of nucleotide dissociation and exchange rates.

Cited by 89 publications

References 38 publications

Structural changes in subdomain 2 of G-actin observed by fluorescence spectroscopy

Structural changes in subdomain 2 of G-actin observed by fluorescence spectroscopy

Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

Biochemical Implications of a Three-Dimensional Model of Monomeric Actin Bound to Magnesium-Chelated ATP

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