2axe

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spinqualitylabelsall models 2axe, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

IODINATED COMPLEX OF ACETYL XYLAN ESTERASE AT 1.80 ANGSTROMS

Overview

Enzymatic and non-enzymatic iodination of the amino acid tyrosine is a, well known phenomenon. The iodination technique has been widely used for, labeling proteins. Using high-resolution X-ray crystallographic, techniques, the chemical and three-dimensional structures of iodotyrosines, formed by non-enzymatic incorporation of I atoms into tyrosine residues of, a crystalline protein are described. Acetylxylan esterase (AXE II; 207, amino-acid residues) from Penicillium purpurogenum has substrate, specificities towards acetate esters of D-xylopyranose residues in xylan, and belongs to a new class of alpha/beta hydrolases. The crystals of the, enzyme are highly ordered, tightly packed and diffract to better than, sub-angstrom resolution at 85 K. The iodination technique has been, utilized to prepare an isomorphous derivative of the AXE II crystal. The, structure of the enzyme determined at 1.10 A resolution exclusively by, normal and anomalous scattering from I atoms, along with the structure of, the iodinated complex at 1.80 A resolution, demonstrate the formation of, covalent bonds between I atoms and C atoms at ortho positions to the, hydroxyl groups of two tyrosyl moieties, yielding iodotyrosines.

About this Structure

2AXE is a Single protein structure of sequence from Penicillium purpurogenum with SO4 as ligand. Active as Acetylesterase, with EC number 3.1.1.6 Full crystallographic information is available from OCA.

Reference

Determination of a protein structure by iodination: the structure of iodinated acetylxylan esterase., Ghosh D, Erman M, Sawicki M, Lala P, Weeks DR, Li N, Pangborn W, Thiel DJ, Jornvall H, Gutierrez R, Eyzaguirre J, Acta Crystallogr D Biol Crystallogr. 1999 Apr;55(Pt 4):779-84. PMID:10089308

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