1m4j
From Proteopedia
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CRYSTAL STRUCTURE OF THE N-TERMINAL ADF-H DOMAIN OF MOUSE TWINFILIN ISOFORM-1
Overview
Twinfilin is an evolutionarily conserved actin monomer-binding protein, that regulates cytoskeletal dynamics in organisms from yeast to mammals., It is composed of two actin-depolymerization factor homology (ADF-H), domains that show approximately 20% sequence identity to ADF/cofilin, proteins. In contrast to ADF/cofilins, which bind both G-actin and F-actin, and promote filament depolymerization, twinfilin interacts only with, G-actin. To elucidate the molecular mechanisms of twinfilin-actin monomer, interaction, we determined the crystal structure of the N-terminal ADF-H, domain of twinfilin and mapped its actin-binding site by site-directed, mutagenesis. This domain has similar overall structure to ADF/cofilins, and the regions important for actin monomer binding in ADF/cofilins are, especially well conserved in twinfilin. Mutagenesis studies show that the, N-terminal ADF-H domain of twinfilin and ADF/cofilins also interact with, actin monomers through similar interfaces, although the binding surface is, slightly extended in twinfilin. In contrast, the regions important for, actin-filament interactions in ADF/cofilins are structurally different in, twinfilin. This explains the differences in actin-interactions (monomer, versus filament binding) between twinfilin and ADF/cofilins. Taken, together, our data show that the ADF-H domain is a structurally conserved, actin-binding motif and that relatively small structural differences at, the actin interfaces of this domain are responsible for the functional, variation between the different classes of ADF-H domain proteins.
About this Structure
1M4J is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Structural conservation between the actin monomer-binding sites of twinfilin and actin-depolymerizing factor (ADF)/cofilin., Paavilainen VO, Merckel MC, Falck S, Ojala PJ, Pohl E, Wilmanns M, Lappalainen P, J Biol Chem. 2002 Nov 8;277(45):43089-95. Epub 2002 Aug 30. PMID:12207032
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