1lcu
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Polylysine Induces an Antiparallel Actin Dimer that Nucleates Filament Assembly: Crystal Structure at 3.5 A Resolution
OverviewOverview
An antiparallel actin dimer has been proposed to be an intermediate, species during actin filament nucleation. We now show that latrunculin A, a marine natural product that inhibits actin polymerization, arrests, polylysine-induced nucleation at the level of an antiparallel dimer, resulting in its accumulation. These dimers, when composed of, pyrene-labeled actin subunits, give rise to a fluorescent excimer, permitting detection during polymerization in vitro. We report the, crystallographic structure of the polylysine-actin-latrunculin A complex, at 3.5-A resolution. The non-crystallographic contact is consistent with a, dimeric structure and confirms the antiparallel orientation of its, subunits. The crystallographic contacts reveal that the mobile DNase I, binding loop of one subunit of a symmetry-related antiparallel actin dimer, is partially stabilized in the interface between the two subunits of a, second antiparallel dimer. These results provide a potential explanation, for the paradoxical nucleation of actin filaments that have exclusively, parallel subunits by a dimer containing antiparallel subunits.
About this StructureAbout this Structure
1LCU is a Single protein structure of sequence from Oryctolagus cuniculus with CA, CL, ATP and LAR as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Polylysine induces an antiparallel actin dimer that nucleates filament assembly: crystal structure at 3.5-A resolution., Bubb MR, Govindasamy L, Yarmola EG, Vorobiev SM, Almo SC, Somasundaram T, Chapman MS, Agbandje-McKenna M, McKenna R, J Biol Chem. 2002 Jun 7;277(23):20999-1006. Epub 2002 Apr 3. PMID:11932258
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