2AXE

IODINATED COMPLEX OF ACETYL XYLAN ESTERASE AT 1.80 ANGSTROMS

Summary for 2AXE

• Entry DOI: 10.2210/pdb2axe/pdb
• Descriptor: ACETYL XYLAN ESTERASE, SULFATE ION (3 entities in total)
• Functional Keywords: hydrolase, iodotyrosines, esterase
• Biological source: Penicillium purpurogenum
• Cellular location: Secreted: O59893
• Total number of polymer chains: 1
• Total formula weight: 21261.45

Authors

Ghosh, D.,Erman, M.,Sawicki, M.W.,Lala, P.,Weeks, D.R.,Li, N.,Pangborn, W.,Thiel, D.J.,Jornvall, H.,Eyzaguirre, J. (deposition date: 1998-09-01, release date: 1999-05-18, Last modification date: 2024-11-20)

Primary citation

Ghosh, D.,Erman, M.,Sawicki, M.,Lala, P.,Weeks, D.R.,Li, N.,Pangborn, W.,Thiel, D.J.,Jornvall, H.,Gutierrez, R.,Eyzaguirre, J.
Determination of a protein structure by iodination: the structure of iodinated acetylxylan esterase.
Acta Crystallogr.,Sect.D, 55:779-784, 1999

PubMed Abstract: 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-angström 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.

PubMed: 10089308
DOI: 10.1107/S0907444999000244

Experimental method

X-RAY DIFFRACTION (1.8 Å)