Abstract
Myosin VI is a reverse direction myosin motor that, as a dimer, moves processively on actin with an average center-of-mass movement of ∼30 nm for each step. We labeled myosin VI with a single fluorophore on either its motor domain or on the distal of two calmodulins (CaMs) located on its putative lever arm. Using a technique called FIONA (fluorescence imaging with one nanometer accuracy), step size was observed with a standard deviation of <1.5 nm, with 0.5-s temporal resolution, and observation times of minutes. Irrespective of probe position, the average step size of a labeled head was ∼60 nm, strongly supporting a hand-over-hand model of motility and ruling out models in which the unique myosin VI insert comes apart. However, the CaM probe displayed large spatial fluctuations (presence of ATP but not ADP or no nucleotide) around the mean position, whereas the motor domain probe did not. This supports a model of myosin VI motility in which the lever arm is either mechanically uncoupled from the motor domain or is undergoing reversible isomerization for part of its motile cycle on actin.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 37223-37226 |
| Number of pages | 4 |
| Journal | Journal of Biological Chemistry |
| Volume | 279 |
| Issue number | 36 |
| DOIs | |
| State | Published - Sep 3 2004 |
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ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology
Cite this
Myosin VI steps via a hand-over-hand mechanism with its lever arm undergoing fluctuations when attached to actin. / Yildiz, Ahmet; Park, Hyokeun; Safer, Dan; Yang, Zhaohui; Chen, Li Qiong; Selvin, Paul R.; Sweeney, H. Lee.
In: Journal of Biological Chemistry, Vol. 279, No. 36, 03.09.2004, p. 37223-37226.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Myosin VI steps via a hand-over-hand mechanism with its lever arm undergoing fluctuations when attached to actin
AU - Yildiz, Ahmet
AU - Park, Hyokeun
AU - Safer, Dan
AU - Yang, Zhaohui
AU - Chen, Li Qiong
AU - Selvin, Paul R.
AU - Sweeney, H. Lee
PY - 2004/9/3
Y1 - 2004/9/3
N2 - Myosin VI is a reverse direction myosin motor that, as a dimer, moves processively on actin with an average center-of-mass movement of ∼30 nm for each step. We labeled myosin VI with a single fluorophore on either its motor domain or on the distal of two calmodulins (CaMs) located on its putative lever arm. Using a technique called FIONA (fluorescence imaging with one nanometer accuracy), step size was observed with a standard deviation of <1.5 nm, with 0.5-s temporal resolution, and observation times of minutes. Irrespective of probe position, the average step size of a labeled head was ∼60 nm, strongly supporting a hand-over-hand model of motility and ruling out models in which the unique myosin VI insert comes apart. However, the CaM probe displayed large spatial fluctuations (presence of ATP but not ADP or no nucleotide) around the mean position, whereas the motor domain probe did not. This supports a model of myosin VI motility in which the lever arm is either mechanically uncoupled from the motor domain or is undergoing reversible isomerization for part of its motile cycle on actin.
AB - Myosin VI is a reverse direction myosin motor that, as a dimer, moves processively on actin with an average center-of-mass movement of ∼30 nm for each step. We labeled myosin VI with a single fluorophore on either its motor domain or on the distal of two calmodulins (CaMs) located on its putative lever arm. Using a technique called FIONA (fluorescence imaging with one nanometer accuracy), step size was observed with a standard deviation of <1.5 nm, with 0.5-s temporal resolution, and observation times of minutes. Irrespective of probe position, the average step size of a labeled head was ∼60 nm, strongly supporting a hand-over-hand model of motility and ruling out models in which the unique myosin VI insert comes apart. However, the CaM probe displayed large spatial fluctuations (presence of ATP but not ADP or no nucleotide) around the mean position, whereas the motor domain probe did not. This supports a model of myosin VI motility in which the lever arm is either mechanically uncoupled from the motor domain or is undergoing reversible isomerization for part of its motile cycle on actin.
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U2 - 10.1074/jbc.C400252200
DO - 10.1074/jbc.C400252200
M3 - Article
C2 - 15254036
AN - SCOPUS:4444364789
VL - 279
SP - 37223
EP - 37226
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 36
ER -