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Enzymatic activity and motility of recombinant Arabidopsis myosin XI, MYA1.
- Source :
-
Plant & cell physiology [Plant Cell Physiol] 2007 Jun; Vol. 48 (6), pp. 886-91. Date of Electronic Publication: 2007 May 15. - Publication Year :
- 2007
-
Abstract
- We expressed recombinant Arabidopsis myosin XI (MYA1), in which the motor domain of MYA1 was connected to an artificial lever arm composed of triple helical repeats of Dictyostelium alpha-actinin, in order to understand its motor activity and intracellular function. The V(max) and K(actin) of the actin-activated Mg(2+) ATPase activity of the recombinant MYA1 were 50.7 Pi head(-1) s(-1) and 30.2 microM, respectively, at 25 degrees C. The recombinant MYA1 could translocate actin filament at the maximum velocity of 1.8 microm s(-1) at 25 degrees C in the in vitro motility assay. The value corresponded to a motility of 3.2 microm s(-1) for native MYA1 if we consider the difference in the lever arm length, and this value was very close to the velocity of cytoplasmic streaming in Arabidopsis hypocotyl epidermal cells. The extent of inhibition by ADP of the motility of MYA1 was similar to that of the well-known processive motor, myosin V, suggesting that MYA1 is a processive motor. The dissociation rate of the actin-MYA1-ADP complex induced by ATP (73.5 s(-1)) and the V(max) value of the actin-activated Mg(2+) ATPase activity revealed that MYA1 stays in the actin-bound state for about 70% of its mechanochemical cycle time. This high ratio of actin-bound states is also a characteristic of processive motors. Our results strongly suggest that MYA1 is a processive motor and involved in vesicle transport and/or cytoplasmic streaming.
- Subjects :
- Actinin chemistry
Actinin genetics
Actinin metabolism
Animals
Arabidopsis genetics
Arabidopsis Proteins chemistry
Arabidopsis Proteins genetics
Cytoplasmic Streaming
Dictyostelium
Gene Expression Regulation, Plant
Molecular Motor Proteins chemistry
Molecular Motor Proteins genetics
Movement
Myosins chemistry
Myosins genetics
Protein Binding
Protein Conformation
Recombinant Proteins chemistry
Recombinant Proteins genetics
Recombinant Proteins metabolism
Arabidopsis metabolism
Arabidopsis Proteins metabolism
Molecular Motor Proteins metabolism
Myosins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0032-0781
- Volume :
- 48
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Plant & cell physiology
- Publication Type :
- Academic Journal
- Accession number :
- 17504816
- Full Text :
- https://doi.org/10.1093/pcp/pcm054