1SJJ

Cryo-EM Structure of Chicken Gizzard Smooth Muscle alpha-Actinin

Summary for 1SJJ

• Entry DOI: 10.2210/pdb1sjj/pdb
• Related: 1AOA 1cfd 1DXX 1HCI 1QAG
• Descriptor: actinin (1 entity in total)
• Functional Keywords: 3-helix bundle, calponin homology domain, calmodulin-like domain, actin binding protein, contractile protein
• Biological source: Gallus gallus (chicken)
• Total number of polymer chains: 2
• Total formula weight: 199746.31

Authors

Liu, J.,Taylor, D.W.,Taylor, K.A. (deposition date: 2004-03-03, release date: 2004-03-23, Last modification date: 2024-02-14)

Primary citation

Liu, J.,Taylor, D.W.,Taylor, K.A.
A 3-D Reconstruction of Smooth Muscle alpha-Actinin by CryoEm Reveals Two Different Conformations at the Actin-binding Region.
J.Mol.Biol., 338:115-125, 2004

PubMed Abstract: Cryoelectron microscopy was used to obtain a 3-D image at 2.0 nm resolution of 2-D arrays of smooth muscle alpha-actinin. The reconstruction reveals a well-resolved long central domain with 90 degrees of left-handed twist and near 2-fold symmetry. However, the molecular ends which contain the actin binding and calmodulin-like domains, have different structures oriented approximately 90 degrees to each other. Atomic structures for the alpha-actinin domains were built by homology modeling and assembled into an atomic model. Model building suggests that in the 2-D arrays, the two calponin homology domains that comprise the actin-binding domain have a closed conformation at one end and an open conformation at the other end due to domain swapping. The open and closed conformations of the actin-binding domain suggests flexibility that may underlie Ca2+ regulation. The approximately 90 degrees orientation difference at the molecular ends may underlie alpha-actinin's ability to crosslink actin filaments in nearly any orientation.

PubMed: 15050827
DOI: 10.1016/j.jmb.2004.02.034

Experimental method

ELECTRON CRYSTALLOGRAPHY (20 Å)