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4pki

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Complex of ATP-actin With the C-terminal Actin-Binding Domain of Tropomodulin

Structural highlights

4pki is a 2 chain structure with sequence from Homo sapiens and Oryctolagus cuniculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.3Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

ACTS_RABIT Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells.

Publication Abstract from PubMed

Proteins that cap the ends of the actin filament are essential regulators of cytoskeleton dynamics. Whereas several proteins cap the rapidly growing barbed end, tropomodulin (Tmod) is the only protein known to cap the slowly growing pointed end. The lack of structural information severely limits our understanding of Tmod's capping mechanism. We describe crystal structures of actin complexes with the unstructured amino-terminal and the leucine-rich repeat carboxy-terminal domains of Tmod. The structures and biochemical analysis of structure-inspired mutants showed that one Tmod molecule interacts with three actin subunits at the pointed end, while also contacting two tropomyosin molecules on each side of the filament. We found that Tmod achieves high-affinity binding through several discrete low-affinity interactions, which suggests a mechanism for controlled subunit exchange at the pointed end.

Actin cytoskeleton. Mechanism of actin filament pointed-end capping by tropomodulin.,Rao JN, Madasu Y, Dominguez R Science. 2014 Jul 25;345(6195):463-7. doi: 10.1126/science.1256159. PMID:25061212^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Rao JN, Madasu Y, Dominguez R. Actin cytoskeleton. Mechanism of actin filament pointed-end capping by tropomodulin. Science. 2014 Jul 25;345(6195):463-7. doi: 10.1126/science.1256159. PMID:25061212 doi:http://dx.doi.org/10.1126/science.1256159