1khi
From Proteopedia
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CRYSTAL STRUCTURE OF HEX1
Overview
The Woronin body is a dense-core vesicle specific to filamentous ascomycetes (Euascomycetes), where it functions to seal the septal pore in response to cellular damage. The HEX-1 protein self-assembles to form this solid core of the vesicle. Here, we solve the crystal structure of HEX-1 at 1.8 A, which provides the structural basis of its self-assembly. The structure reveals the existence of three intermolecular interfaces that promote the formation of a three-dimensional protein lattice. Consistent with these data, self-assembly is disrupted by mutations in intermolecular contact residues and expression of an assembly-defective HEX-1 mutant results in the production of aberrant Woronin bodies, which possess a soluble noncrystalline core. This mutant also fails to complement a hex-1 deletion in Neurospora crassa, demonstrating that the HEX-1 protein lattice is required for Woronin body function. Although both the sequence and the tertiary structure of HEX-1 are similar to those of eukaryotic initiation factor 5A (eIF-5A), the amino acids required for HEX-1 self-assembly and peroxisomal targeting are absent in eIF-5A. Thus, we propose that a new function has evolved following duplication of an ancestral eIF-5A gene and that this may define an important step in fungal evolution.
About this Structure
1KHI is a Single protein structure of sequence from Neurospora crassa. Full crystallographic information is available from OCA.
Reference
A HEX-1 crystal lattice required for Woronin body function in Neurospora crassa., Yuan P, Jedd G, Kumaran D, Swaminathan S, Shio H, Hewitt D, Chua NH, Swaminathan K, Nat Struct Biol. 2003 Apr;10(4):264-70. PMID:12640443
Page seeded by OCA on Thu Feb 21 13:34:12 2008
