Unidirectional Brownian motion observed in an in silico single molecule experiment of an actomyosin motor.
The actomyosin molecular motor, the motor composed of myosin II and actin filament, is responsible for muscle contraction, converting chemical energy into mechanical work. Although recent single molecule and structural studies have shed new light on the energy-converting mechanism, the physical basis of the molecular-level mechanism remains unclear because of the experimental limitations. To provide a clue to resolve the controversy between the lever-arm mechanism and the Brownian ratchet-like mechanism, we here report an in silico single molecule experiment of an actomyosin motor. When we placed myosin on an actin filament and allowed myosin to move along the filament, we found that myosin exhibits a unidirectional Brownian motion along the filament. This unidirectionality was found to arise from the combination of a nonequilibrium condition realized by coupling to the ATP hydrolysis and a ratchet-like energy landscape inherent in the actin-myosin interaction along the filament, indicating that a Brownian ratchet-like mechanism contributes substantially to the energy conversion of this molecular motor.
Takano
Mitsunori
M
Department of Physics, Waseda University, Okubo 3-4-1, Shinjuku-Ku, Tokyo 169-8555, Japan. mtkn@waseda.jp
Terada
Tomoki P
TP
Sasai
Masaki
M
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002645:Chickens; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009068:Movement / Q000502:physiology*; D016296:Mutagenesis; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D013269:Stochastic Processes
D000199:Actins; D020409:Molecular Motor Proteins; D000255:Adenosine Triphosphate; D009218:Myosins
Science. 2001 Jul 27;293(5530):708-11
11474115
J Muscle Res Cell Motil. 1984 Aug;5(4):351-61
6237117
Biophys J. 2005 Mar;88(3):2068-77
15626711
Proc Natl Acad Sci U S A. 1997 Aug 5;94(16):8533-8
9238011
Nature. 2002 Jan 10;415(6868):129-31
11805818
Proc Natl Acad Sci U S A. 2008 Jun 3;105(22):7714-9
18509050
Curr Opin Struct Biol. 2001 Apr;11(2):182-94
11297926
Science. 1991 Dec 13;254(5038):1598-603
1749933
Proc Natl Acad Sci U S A. 1997 May 27;94(11):5646-50
9159126
Biophys J. 1998 Oct;75(4):1886-94
9746529
Nature. 1994 Mar 10;368(6467):113-9
8139653
Nature. 2003 Jul 31;424(6948):574-7
12891363
Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):14949-54
11734631
Science. 1997 May 9;276(5314):917-22
9139648
J Biol Chem. 2001 Feb 2;276(5):2998-3003
11042210
Biochemistry. 1971 Dec 7;10(25):4617-24
4258719
Proc Natl Acad Sci U S A. 1999 Jan 19;96(2):465-70
9892656
Nature. 2009 Jan 22;457(7228):441-5
19158791
Biophys J. 2001 Jan;80(1):505-15
11159421
Nat Cell Biol. 2002 Jan;4(1):59-65
11740494
Science. 1993 Jul 2;261(5117):50-8
8316857
Science. 2007 May 25;316(5828):1208-12
17525343
Proc Natl Acad Sci U S A. 2005 Sep 27;102(39):13873-8
16150709
Nature. 1987 Apr 23-29;326(6115):805-8
3574452
Curr Biol. 1997 Feb 1;7(2):R112-8
9081660
Nature. 1999 Jan 14;397(6715):129-34
9923673
Genes Cells. 2000 Jan;5(1):9-16
10651901
Biophys J. 2007 Aug 1;93(3):895-901
17496039
Mol Cell. 2005 Sep 2;19(5):595-605
16137617
Nat Struct Mol Biol. 2007 Mar;14(3):246-8
17293871
Science. 1995 Mar 17;267(5204):1619-20
7886447
Cell. 1999 Nov 12;99(4):421-31
10571184
Science. 1993 Jul 2;261(5117):58-65
8316858
Nature. 1995 Nov 9;378(6553):209-12
7477328
Proc Natl Acad Sci U S A. 1991 Sep 1;88(17):7711-4
1831905
Proc Natl Acad Sci U S A. 1993 Mar 15;90(6):2127-31
8460118
Proc Natl Acad Sci U S A. 2008 Jun 24;105(25):8631-6
18552179
Nat Chem Biol. 2009 Jun;5(6):403-5
19430485
Proc Natl Acad Sci U S A. 2002 Jul 9;99(14):9202-6
12082180
Nat Struct Biol. 2003 Oct;10(10):831-5
14502269
Philos Trans R Soc Lond B Biol Sci. 2004 Dec 29;359(1452):1913-20
15647167
Biopolymers. 1992 Jun;32(6):695-709
1643270
Protein Sci. 2000 Sep;9(9):1753-73
11045621
Biophys J. 2008 Dec 15;95(12):5820-31
18931255
Nature. 2003 Sep 25;425(6956):423-7
14508495
Structure. 2003 Dec;11(12):1621-7
14656445