3GN4

Myosin lever arm

Summary for 3GN4

• Entry DOI: 10.2210/pdb3gn4/pdb
• Descriptor: Myosin-VI, Calmodulin, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: unconventional myosin, motility, lever arm, 3-helix bundle, actin-binding, atp-binding, calmodulin-binding, coiled coil, cytoplasm, endocytosis, golgi apparatus, hearing, membrane, motor protein, myosin, nucleotide-binding, nucleus, phosphoprotein, protein transport, transport, acetylation, calcium, motor protein-metal binding protein complex
• Biological source: Sus scrofa (pig); More
• Cellular location: Golgi apparatus, trans-Golgi network membrane; Peripheral membrane protein (By similarity): Q29122
• Total number of polymer chains: 6
• Total formula weight: 102513.10

Authors

Mukherjea, M.,Llinas, P.,Kim, H.,Travaglia, M.,Safer, D.,Zong, A.B.,Menetrey, J.,Franzini-Armstrong, C.,Selvin, P.R.,Houdusse, A.,Sweeney, H.L. (deposition date: 2009-03-16, release date: 2009-09-08, Last modification date: 2023-09-06)

Primary citation

Mukherjea, M.,Llinas, P.,Kim, H.,Travaglia, M.,Safer, D.,Menetrey, J.,Franzini-Armstrong, C.,Selvin, P.R.,Houdusse, A.,Sweeney, H.L.
Myosin VI dimerization triggers an unfolding of a three-helix bundle in order to extend its reach
Mol.Cell, 35:305-315, 2009

PubMed Abstract: Myosin VI challenges the prevailing theory of how myosin motors move on actin: the lever arm hypothesis. While the reverse directionality and large powerstroke of myosin VI can be attributed to unusual properties of a subdomain of the motor (converter with a unique insert), these adaptations cannot account for the large step size on actin. Either the lever arm hypothesis needs modification, or myosin VI has some unique form of extension of its lever arm. We determined the structure of the region immediately distal to the lever arm of the motor and show that it is a three-helix bundle. Based on C-terminal truncations that display the normal range of step sizes on actin, CD, fluorescence studies, and a partial deletion of the bundle, we demonstrate that this bundle unfolds upon dimerization of two myosin VI monomers. This unconventional mechanism generates an extension of the lever arm of myosin VI.

PubMed: 19664948
DOI: 10.1016/j.molcel.2009.07.010

Experimental method

X-RAY DIFFRACTION (2.7 Å)