Open AccessCrystallization and preliminary X‐ray diffraction studies of the glutaminyl cyclase from Carica papaya latex
Author(s) -
Azarkan Mohamed,
Clantin Bernard,
Bompard Coralie,
Belrhali Hassan,
BaeyensVolant Danielle,
Looze Yvan,
Villeret Vincent,
Wintjens René
Publication year - 2005
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309104025904
Subject(s) - carica , chemistry , enzyme , crystallization , proteolysis , orthorhombic crystal system , crystallography , cyclase , biochemistry , organic chemistry , biology , crystal structure , botany
In living systems, the intramolecular cyclization of N‐terminal glutamine residues is accomplished by glutaminyl cyclase enzymes (EC 2.3.2.5). While in mammals these enzymes are involved in the synthesis of hormonal and neurotransmitter peptides, the physiological role played by the corresponding plant enzymes still remains to be unravelled. Papaya glutaminyl cyclase (PQC), a 33 kDa enzyme found in the latex of the tropical tree Carica papaya , displays an exceptional resistance to chemical and thermal denaturation as well as to proteolysis. In order to elucidate its enzymatic mechanism and to gain insights into the structural determinants underlying its remarkable stability, PQC was isolated from papaya latex, purified and crystallized by the hanging‐drop vapour‐diffusion method. The crystals belong to the orthorhombic space group P 2 1 2 1 2 1 , with unit‐cell parameters a = 62.82, b = 81.23, c = 108.17 Å and two molecules per asymmetric unit. Diffraction data have been collected at ESRF beamline BM14 and processed to a resolution of 1.7 Å.