2EYI

Crystal structure of the actin-binding domain of human alpha-actinin 1 at 1.7 Angstrom resolution

Summary for 2EYI

• Entry DOI: 10.2210/pdb2eyi/pdb
• Related: 2eyn
• Descriptor: Alpha-actinin 1 (2 entities in total)
• Functional Keywords: calponin homology domain, ch domain, structural protein, actin-binding, actin-crosslinking, actin-bundling
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm, cytoskeleton : P12814
• Total number of polymer chains: 1
• Total formula weight: 26572.68

Authors

Borrego-Diaz, E.,Kerff, F.,Lee, S.H.,Ferron, F.,Li, Y.,Dominguez, R. (deposition date: 2005-11-09, release date: 2006-08-29, Last modification date: 2023-08-23)

Primary citation

Borrego-Diaz, E.,Kerff, F.,Lee, S.H.,Ferron, F.,Li, Y.,Dominguez, R.
Crystal structure of the actin-binding domain of alpha-actinin 1: Evaluating two competing actin-binding models.
J.Struct.Biol., 155:230-238, 2006

PubMed Abstract: Alpha-actinin belongs to the spectrin family of actin crosslinking and bundling proteins that function as key regulators of cell motility, morphology and adhesion. The actin-binding domain (ABD) of these proteins consists of two consecutive calponin homology (CH) domains. Electron microscopy studies on ABDs appear to support two competing actin-binding models, extended and compact, whereas the crystal structures typically display a compact conformation. We have determined the 1.7A resolution structure of the ABD of alpha-actinin 1, a ubiquitously expressed isoform. The structure displays the classical compact conformation. We evaluated the two binding models by surface conservation analysis. The results show a conserved surface that spans both domains and corresponds to two previously identified actin-binding sites (ABS2 and ABS3). A third, and probably less important site, ABS1, is mostly buried in the compact conformation. However, a thorough examination of existing structures suggests a weak and semi-polar binding interface between the two CHs, leaving open the possibility of domain reorientation or opening. Our results are consistent with a two-step binding mechanism in which the ABD interacts first in the compact form observed in the structures, and then transitions toward a higher affinity state, possibly through minor rearrangement of the domains.

PubMed: 16698282
DOI: 10.1016/j.jsb.2006.01.013

Experimental method

X-RAY DIFFRACTION (1.7 Å)