PDBsum entry: 1tjt

Contractile protein

PDB id: 1tjt

Contents

Protein chain

224 a.a. *

Waters ×193

* Residue conservation analysis

PDB id:

1tjt

Name:

Contractile protein

Title:

X-ray structure of the human alpha-actinin isoform 3 at 2.2a resolution

Structure:

Alpha-actinin 3. Chain: a. Fragment: actin binding domain. Synonym: alpha actinin skeletal muscle isoform 3, f-actin cross linking protein. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: actn3. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.19Å R-factor: 0.227 R-free: 0.273

Authors:

G.Franzot,B.Sjoblom,M.Gautel,K.Djinovic Carugo

Key ref:

G.Franzot et al. (2005). The crystal structure of the actin binding domain from alpha-actinin in its closed conformation: structural insight into phospholipid regulation of alpha-actinin. J Mol Biol, 348, 151-165. PubMed id: 15808860 DOI: 10.1016/j.jmb.2005.01.002

Date:

07-Jun-04 Release date: 17-May-05

Protein chain

Q08043  (ACTN3_HUMAN) -  Alpha-actinin-3

Seq: 901 a.a.

Struc: 224 a.a.

 Gene Ontology (GO) functional annotation 

• Biochemical function: actin binding (1 term)

DOI no: 10.1016/j.jmb.2005.01.002

J Mol Biol 348:151-165 (2005)

PubMed id: 15808860

The crystal structure of the actin binding domain from alpha-actinin in its closed conformation: structural insight into phospholipid regulation of alpha-actinin.

G.Franzot, B.Sjöblom, M.Gautel, K.Djinović Carugo.

ABSTRACT

Alpha-actinin is the major F-actin crosslinking protein in both muscle and non-muscle cells. We report the crystal structure of the actin binding domain of human muscle alpha-actinin-3, which is formed by two consecutive calponin homology domains arranged in a "closed" conformation. Structural studies and available biochemical data on actin binding domains suggest that two calponin homology domains come in a closed conformation in the native apo-form, and that conformational changes involving the relative orientation of the two calponin homology domains are required for efficient binding to actin filaments. The actin binding activity of muscle isoforms is supposed to be regulated by phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), which binds to the second calponin homology domain. On the basis of structural analysis we propose a distinct binding site for PtdIns(4,5)P2, where the fatty acid moiety would be oriented in a direction that allows it to interact with the linker sequence between the actin binding domain and the first spectrin-like repeat, regulating thereby the binding of the C-terminal calmodulin-like domain to this linker.

Selected figure(s)

Figure 2.
Figure 2. (a) Structural superposition of ABDs from a-actinin and plectin made by TOPP. The color code for ABD from a-actinin is as in Figure 1, plectin is shown in blue. The superimposed proteins are oriented according to Figure 1. The Figure was prepared by PyMOL. (b) Structural superposition of ABDs from a-actinin and utrophin was made by TOPP. The color code for ABD from a-actinin is as in Figure 1, utrophin subunits are shown in yellow and in blue. The superimposed proteins are oriented according to Figure 1. The Figure was prepared by PyMOL.

Figure 3.
Figure 3. Dendrogram showing the classification of CH domains on the basis of their 3D structure.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2005, 348, 151-165) copyright 2005.

Figures were selected by an automated process.