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Structures of the N ‐acetyltransferase domain of Xylella fastidiosa N ‐acetyl‐L‐glutamate synthase/kinase with and without a His tag bound to N ‐acetyl‐L‐glutamate
Author(s) -
Zhao Gengxiang,
Jin Zhongmin,
Allewell Norma M.,
Tuchman Mendel,
Shi Dashuang
Publication year - 2015
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x14026788
Subject(s) - xylella fastidiosa , acetyltransferase , glutamate synthase , chemistry , atp synthase , biochemistry , glutamate receptor , enzyme , biology , bacteria , gene , glutamate dehydrogenase , receptor , acetylation , genetics
Structures of the catalytic N ‐acetyltransferase (NAT) domain of the bifunctional N ‐acetyl‐L‐glutamate synthase/kinase (NAGS/K) from Xylella fastidiosa bound to N ‐acetyl‐L‐glutamate (NAG) with and without an N‐terminal His tag have been solved and refined at 1.7 and 1.4 Å resolution, respectively. The NAT domain with an N‐terminal His tag crystallized in space group P 4 1 2 1 2, with unit‐cell parameters a = b = 51.72, c = 242.31 Å. Two subunits form a molecular dimer in the asymmetric unit, which contains ∼41% solvent. The NAT domain without an N‐terminal His tag crystallized in space group P 2 1 , with unit‐cell parameters a = 63.48, b = 122.34, c = 75.88 Å, β = 107.6°. Eight subunits, which form four molecular dimers, were identified in the asymmetric unit, which contains ∼38% solvent. The structures with and without the N‐terminal His tag provide an opportunity to evaluate how the His tag affects structure and function. Furthermore, multiple subunits in different packing environments allow an assessment of the plasticity of the NAG binding site, which might be relevant to substrate binding and product release. The dimeric structure of the X. fastidiosa N ‐acetytransferase (xfNAT) domain is very similar to that of human N ‐acetyltransferase (hNAT), reinforcing the notion that mammalian NAGS is evolutionally derived from bifunctional bacterial NAGS/K.