1C1G

CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYSTAL FORM

Summary for 1C1G

• Entry DOI: 10.2210/pdb1c1g/pdb
• Descriptor: TROPOMYOSIN (1 entity in total)
• Functional Keywords: tropomyosin coiled-coil alpha-helical, contractile protein
• Biological source: Sus scrofa (pig)
• Cellular location: Cytoplasm, cytoskeleton : P42639
• Total number of polymer chains: 4
• Total formula weight: 131138.55

Authors

Whitby, F.G.,Phillips Jr., G.N. (deposition date: 1999-07-22, release date: 2000-02-11, Last modification date: 2024-02-07)

Primary citation

Whitby, F.G.,Phillips Jr., G.N.
Crystal structure of tropomyosin at 7 Angstroms resolution.
Proteins, 38:49-59, 2000

PubMed Abstract: Tropomyosin is a 400A-long coiled coil that polymerizes to form a continuous filament that associates with actin in muscle and numerous non-muscle cells. Tropomyosin and troponin together form a calcium-sensitive switch that is responsible for thin-filament regulation of striated muscle. Subtle structural features of the molecule, including non-canonical aspects of its coiled-coil motif, undoubtedly influence its association with f-actin and its role in thin filament regulation. Previously, careful inspection of native diffraction intensities was sufficient to construct a model of tropomyosin at 9A resolution in a spermine-induced crystal form that diffracts anisotropically to 4A resolution. Single isomorphous replacement (SIR) phasing has now provided an empirical determination of the structure at 7A resolution. A novel method of heavy-atom analysis was used to overcome difficulties in interpretation of extremely anisotropic diffraction. The packing arrangement of the molecules in the crystal, and important aspects of the tropomyosin geometry such as non-uniformities of the pitch and variable bending and radius of the coiled coil are evident.

PubMed: 10651038
DOI: 10.1002/(SICI)1097-0134(20000101)38:1<49::AID-PROT6>3.3.CO;2-2

Experimental method

X-RAY DIFFRACTION (7 Å)