1g6e
|
ANTIFUNGAL PROTEIN FROM STREPTOMYCES TENDAE TU901, 30-CONFORMERS ENSEMBLE
OverviewOverview
AFP1 is a recently discovered anti-fungal, chitin-binding protein from, Streptomyces tendae Tu901. Mature AFP1 comprises 86 residues and exhibits, limited sequence similarity to the cellulose-binding domains of bacterial, cellulases and xylanases. No similarity to the Cys and Gly-rich domains of, plant chitin-binding proteins (e.g. agglutinins, lectins, hevein) is, observed. AFP1 is the first chitin-binding protein from a bacterium for, which anti-fungal activity was shown. Here, we report the, three-dimensional solution structure of AFP1, determined by nuclear, magnetic resonance spectroscopy. The protein contains two antiparallel, beta-sheets (five and four beta-strands each), that pack against each, other in a parallel beta-sandwich. This type of architecture is conserved, in the functionally related family II of cellulose-binding domains, albeit, with different connectivity. A similar fold is also observed in other, unrelated proteins (spore coat protein from Myxococcus xanthus, beta-B2, and gamma-B crystallins from Bos taurus, canavalin from Jack bean). AFP1, is therefore classified as a new member of the betagamma-crystallin, superfamily. The dynamics of the protein was characterized by NMR using, amide 15N relaxation and solvent exchange data. We demonstrate that the, protein exhibits an axially symmetric (oblate-like) rotational diffusion, tensor whose principal axis coincides to within 15 degrees with that of, the inertial tensor. After completion of the present structure of AFP1, an, identical fold was reported for a Streptomyces killer toxin-like protein., Based on sequence comparisons and clustering of conserved residues on the, protein surface for different cellulose and chitin-binding proteins, we, postulate a putative sugar-binding site for AFP1. The inability of the, protein to bind short chitin fragments suggests that certain particular, architectural features of the solid chitin surface are crucial for the, interaction.
About this StructureAbout this Structure
1G6E is a Single protein structure of sequence from Streptomyces tendae. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure, backbone dynamics and chitin binding of the anti-fungal protein from Streptomyces tendae TU901., Campos-Olivas R, Horr I, Bormann C, Jung G, Gronenborn AM, J Mol Biol. 2001 May 11;308(4):765-82. PMID:11350173
Page seeded by OCA on Sun Nov 25 00:55:15 2007