2dfs
From Proteopedia
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3-D structure of Myosin-V inhibited state
Overview
Unconventional myosin V (myoV) is an actin-based molecular motor that has, a key function in organelle and mRNA transport, as well as in membrane, trafficking. MyoV was the first member of the myosin superfamily shown to, be processive, meaning that a single motor protein can 'walk', hand-over-hand along an actin filament for many steps before detaching., Full-length myoV has a low actin-activated MgATPase activity at low, [Ca2+], whereas expressed constructs lacking the cargo-binding domain have, a high activity regardless of [Ca2+] (refs 5-7). Hydrodynamic data and, electron micrographs indicate that the active state is extended, whereas, the inactive state is compact. Here we show the first three-dimensional, structure of the myoV inactive state. Each myoV molecule consists of two, heads that contain an amino-terminal motor domain followed by a lever arm, that binds six calmodulins. The heads are followed by a coiled-coil, dimerization domain (S2) and a carboxy-terminal globular cargo-binding, domain. In the inactive structure, bending of myoV at the head-S2 junction, places the cargo-binding domain near the motor domain's ATP-binding, pocket, indicating that ATPase inhibition might occur through decreased, rates of nucleotide exchange. The actin-binding interfaces are, unobstructed, and the lever arm is oriented in a position typical of, strong actin-binding states. This structure indicates that motor recycling, after cargo delivery might occur through transport on actively, treadmilling actin filaments rather than by diffusion.
About this Structure
2DFS is a Protein complex structure of sequences from Gallus gallus and Mus musculus. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of the myosin V inhibited state by cryoelectron tomography., Liu J, Taylor DW, Krementsova EB, Trybus KM, Taylor KA, Nature. 2006 Jul 13;442(7099):208-11. Epub 2006 Apr 16. PMID:16625208
Page seeded by OCA on Wed Nov 21 09:35:27 2007
