1j0b

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spinqualitylabelsall models 1j0b, resolution 2.7Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure Analysis of the ACC deaminase homologue complexed with inhiitor

Overview

1-Aminocyclopropane-l-carboxylate deaminase (ACCD) is a pyridoxal, 5/-phosphate dependent enzyme that shows deaminase activity toward ACC, a, precursor of plant hormone ethylene. ACCD from some soil bacteria has been, reported to be able to break the cyclopropane ring of ACC to yield, a-ketobutyrate and ammonia. We reported the crystal structure of ACCD from, the yeast Hansenula saturnus in the absence/presence of substrate ACC, and, proposed its ingenious reaction mechanisms. In order to study the enzyme, further, we overexpressed the ACCD homologue protein (phAHP) from the, fully decoded hyperthermophilic archearon, Pyrococcus horikoshii OT3., However, phAHP does not show ACCD activity at high temperature as well as, at room temperature, though it has significant sequence similarity., Instead of ACCD activity, the GC-MS analysis and enzymatic method show, that phAHP has deaminase activity toward L and D-serine. Here, we present, the crystal structures of the native and ACC-complexed phAHP. The overall, topology of the phAHP structure is very similar to that of ACCD; however, critical differences were observed around the active site. Here, the, differences of enzymatic activity between phAHP and ACCD are discussed, based on the structural differences of these two proteins. We suggest that, the catalytic disagreement between these two enzymes comes from the, difference of the residues near the pyridine ring of pyridoxal, 5'-phosphate (PLP), not the difference of the catalytic residues, themselves. We also propose a condition necessary in the primary sequence, to have ACCD activity.

About this Structure

1J0B is a Single protein structure of sequence from Pyrococcus horikoshii with 5PA as ligand. Active as 1-aminocyclopropane-1-carboxylate deaminase, with EC number 3.5.99.7 Full crystallographic information is available from OCA.

Reference

Structural and enzymatic properties of 1-aminocyclopropane-1-carboxylate deaminase homologue from Pyrococcus horikoshii., Fujino A, Ose T, Yao M, Tokiwano T, Honma M, Watanabe N, Tanaka I, J Mol Biol. 2004 Aug 20;341(4):999-1013. PMID:15328614

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