Abstract
Load dependence of the lifetime of the rigor bonds formed between a single myosin molecule (either heavy meromyosin, HMM, or myosin subfragment-1, S1) and actin filament was examined in the absence of nucleotide by pulling the barbed end of the actin filament with optical tweezers. For S1, the relationship between the lifetime (τ) and the externally imposed load (F) at absolute temperature T could be expressed as τ(F) = τ(0)·exp(-F·d/k(B)T) with τ(0) of 67 s and an apparent interaction distance d of 2.4 nm (k(B) is the Boltzmann constant). The relationship for HMM was expressed by the sum of two exponentials, with two sets of τ(0) and d being, respectively, 62 s and 2.7 nm, and 950 s and 1.4 nm. The fast component of HMM coincides with τ(F) for S1, suggesting that the fast component corresponds to single-headed binding and the slow component to double-headed binding. These large interaction distances, which may be a common characteristic of motor proteins, are attributed to the geometry for applying an external load. The pulling experiment has also allowed direct estimation of the number of myosin molecules interacting with an actin filament. Actin filaments tethered to a single HMM molecule underwent extensive rotational Brownian motion, indicating a low torsional stiffness for HMM. From these results, we discuss the characteristics of interaction between actin and myosin, with the focus on the manner of binding of myosin.
| Original language | English |
|---|---|
| Pages (from-to) | 962-974 |
| Number of pages | 13 |
| Journal | Biophysical Journal |
| Volume | 79 |
| Issue number | 2 |
| Publication status | Published - 2000 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biophysics
Cite this
Characterization of single actomyosin rigor bonds : Load dependence of lifetime and mechanical properties. / Nishizaka, Takayuki; Seo, Ryuzo; Tadakuma, Hisashi; Kinosita, Kazuhiko; Ishiwata, Shin'ichi.
In: Biophysical Journal, Vol. 79, No. 2, 2000, p. 962-974.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of single actomyosin rigor bonds
T2 - Load dependence of lifetime and mechanical properties
AU - Nishizaka, Takayuki
AU - Seo, Ryuzo
AU - Tadakuma, Hisashi
AU - Kinosita, Kazuhiko
AU - Ishiwata, Shin'ichi
PY - 2000
Y1 - 2000
N2 - Load dependence of the lifetime of the rigor bonds formed between a single myosin molecule (either heavy meromyosin, HMM, or myosin subfragment-1, S1) and actin filament was examined in the absence of nucleotide by pulling the barbed end of the actin filament with optical tweezers. For S1, the relationship between the lifetime (τ) and the externally imposed load (F) at absolute temperature T could be expressed as τ(F) = τ(0)·exp(-F·d/k(B)T) with τ(0) of 67 s and an apparent interaction distance d of 2.4 nm (k(B) is the Boltzmann constant). The relationship for HMM was expressed by the sum of two exponentials, with two sets of τ(0) and d being, respectively, 62 s and 2.7 nm, and 950 s and 1.4 nm. The fast component of HMM coincides with τ(F) for S1, suggesting that the fast component corresponds to single-headed binding and the slow component to double-headed binding. These large interaction distances, which may be a common characteristic of motor proteins, are attributed to the geometry for applying an external load. The pulling experiment has also allowed direct estimation of the number of myosin molecules interacting with an actin filament. Actin filaments tethered to a single HMM molecule underwent extensive rotational Brownian motion, indicating a low torsional stiffness for HMM. From these results, we discuss the characteristics of interaction between actin and myosin, with the focus on the manner of binding of myosin.
AB - Load dependence of the lifetime of the rigor bonds formed between a single myosin molecule (either heavy meromyosin, HMM, or myosin subfragment-1, S1) and actin filament was examined in the absence of nucleotide by pulling the barbed end of the actin filament with optical tweezers. For S1, the relationship between the lifetime (τ) and the externally imposed load (F) at absolute temperature T could be expressed as τ(F) = τ(0)·exp(-F·d/k(B)T) with τ(0) of 67 s and an apparent interaction distance d of 2.4 nm (k(B) is the Boltzmann constant). The relationship for HMM was expressed by the sum of two exponentials, with two sets of τ(0) and d being, respectively, 62 s and 2.7 nm, and 950 s and 1.4 nm. The fast component of HMM coincides with τ(F) for S1, suggesting that the fast component corresponds to single-headed binding and the slow component to double-headed binding. These large interaction distances, which may be a common characteristic of motor proteins, are attributed to the geometry for applying an external load. The pulling experiment has also allowed direct estimation of the number of myosin molecules interacting with an actin filament. Actin filaments tethered to a single HMM molecule underwent extensive rotational Brownian motion, indicating a low torsional stiffness for HMM. From these results, we discuss the characteristics of interaction between actin and myosin, with the focus on the manner of binding of myosin.
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M3 - Article
C2 - 10920026
AN - SCOPUS:0033884332
VL - 79
SP - 962
EP - 974
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 2
ER -