Abstract
The changes in F-actin conformation of myosin-free single ghost fibre induced by binding of phosphorylated or dephosphorylated heavy meromyosin have been studied by measuring polarized fluorescence of F-actin intrinsic tryptophan and of phalloidin-rhodamin bound to F-actin. The changes of polarization of both fluorescences were found to be dependent on low or high Ca2+ concenration and on the phosphorylated or dephosphorylated form of heavy meromyosin. Computer analysis of polarized fluorescence has shown that binding of phosphorylated heavy meromyosin with divalent ion binding sites saturated with Mg2+ (in the presence of 1 mM MgCl2 and 1 mM EGTA) and dephosphorylated heavy meromyosin with divalent ion binding sites saturated with Ca2+ (in the presence of 1 mM MgCl2 and 0.1 mM Ca2+) decreases the angles of emission and absorption dipoles and the angle between the F-actin axis and the fibre axis, thus suggesting that F-actin in ghost fibre becomes more flexible. On the other hand, the above-mentioned angles increase when phosphorylated heavy meromyosin at high and dephosphorylated heavy meromyosin at low Ca2+ concentration were bound to thin filaments, thus showing the decrease of F-actin flexibility under these conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 1-9 |
| Number of pages | 9 |
| Journal | Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular |
| Volume | 913 |
| Issue number | 1 |
| DOIs | |
| State | Published - May 27 1987 |
| Externally published | Yes |
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Keywords
- F-actin
- Fluorescence, polarized
- Ghost fibre, myosin-free
- Heavy meromyosin, (de)phosphorylated
- Myosin
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology
- Structural Biology
Cite this
Conformational changes of F-actin in myosin-free ghost single fibre induced by either phosphorylated or dephosphorylated heavy meromyosin. / Kâkol, Irena; Borovikov, Yurii S.; Szczesna-Cordary, Danuta; Kirillina, Valentina P.; Levitsky, Dimitrii I.
In: Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular, Vol. 913, No. 1, 27.05.1987, p. 1-9.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Conformational changes of F-actin in myosin-free ghost single fibre induced by either phosphorylated or dephosphorylated heavy meromyosin
AU - Kâkol, Irena
AU - Borovikov, Yurii S.
AU - Szczesna-Cordary, Danuta
AU - Kirillina, Valentina P.
AU - Levitsky, Dimitrii I.
PY - 1987/5/27
Y1 - 1987/5/27
N2 - The changes in F-actin conformation of myosin-free single ghost fibre induced by binding of phosphorylated or dephosphorylated heavy meromyosin have been studied by measuring polarized fluorescence of F-actin intrinsic tryptophan and of phalloidin-rhodamin bound to F-actin. The changes of polarization of both fluorescences were found to be dependent on low or high Ca2+ concenration and on the phosphorylated or dephosphorylated form of heavy meromyosin. Computer analysis of polarized fluorescence has shown that binding of phosphorylated heavy meromyosin with divalent ion binding sites saturated with Mg2+ (in the presence of 1 mM MgCl2 and 1 mM EGTA) and dephosphorylated heavy meromyosin with divalent ion binding sites saturated with Ca2+ (in the presence of 1 mM MgCl2 and 0.1 mM Ca2+) decreases the angles of emission and absorption dipoles and the angle between the F-actin axis and the fibre axis, thus suggesting that F-actin in ghost fibre becomes more flexible. On the other hand, the above-mentioned angles increase when phosphorylated heavy meromyosin at high and dephosphorylated heavy meromyosin at low Ca2+ concentration were bound to thin filaments, thus showing the decrease of F-actin flexibility under these conditions.
AB - The changes in F-actin conformation of myosin-free single ghost fibre induced by binding of phosphorylated or dephosphorylated heavy meromyosin have been studied by measuring polarized fluorescence of F-actin intrinsic tryptophan and of phalloidin-rhodamin bound to F-actin. The changes of polarization of both fluorescences were found to be dependent on low or high Ca2+ concenration and on the phosphorylated or dephosphorylated form of heavy meromyosin. Computer analysis of polarized fluorescence has shown that binding of phosphorylated heavy meromyosin with divalent ion binding sites saturated with Mg2+ (in the presence of 1 mM MgCl2 and 1 mM EGTA) and dephosphorylated heavy meromyosin with divalent ion binding sites saturated with Ca2+ (in the presence of 1 mM MgCl2 and 0.1 mM Ca2+) decreases the angles of emission and absorption dipoles and the angle between the F-actin axis and the fibre axis, thus suggesting that F-actin in ghost fibre becomes more flexible. On the other hand, the above-mentioned angles increase when phosphorylated heavy meromyosin at high and dephosphorylated heavy meromyosin at low Ca2+ concentration were bound to thin filaments, thus showing the decrease of F-actin flexibility under these conditions.
KW - F-actin
KW - Fluorescence, polarized
KW - Ghost fibre, myosin-free
KW - Heavy meromyosin, (de)phosphorylated
KW - Myosin
UR - http://www.scopus.com/inward/record.url?scp=0023279088&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023279088&partnerID=8YFLogxK
U2 - 10.1016/0167-4838(87)90225-1
DO - 10.1016/0167-4838(87)90225-1
M3 - Article
C2 - 3555620
AN - SCOPUS:0023279088
VL - 913
SP - 1
EP - 9
JO - Biochimica et Biophysica Acta - Proteins and Proteomics
JF - Biochimica et Biophysica Acta - Proteins and Proteomics
SN - 1570-9639
IS - 1
ER -