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New crystal form of human ubiquitin in the presence of magnesium
Author(s) -
CamaraArtigas Ana,
PlazaGarrido Marina,
MartinezRodriguez Sergio,
Bacarizo Julio
Publication year - 2016
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/s2053230x15023390
Subject(s) - crystallography , triclinic crystal system , magnesium , crystal structure , crystallization , crystal (programming language) , ubiquitin , chemistry , molecule , materials science , biochemistry , organic chemistry , computer science , gene , programming language
Ubiquitin is a small globular protein that has a considerable number of lysine residues on its surface. This results in a high surface entropy that precludes the formation of crystal‐packing interactions. To date, only a few structures of the native form of ubiquitin have been solved, and most of the crystals that led to these structures were obtained in the presence of different divalent metal cations. In this work, a new crystallographic structure of human ubiquitin solved from crystals grown in the presence of magnesium is presented. The crystals belonged to a triclinic space group, with unit‐cell parameters a = 29.96, b = 30.18, c = 41.41 Å, α = 88.52, β = 79.12, γ = 67.37°. The crystal lattice is composed of stacked layers of human ubiquitin molecules with a large hydrophobic interface and a smaller polar interface in which the magnesium ion lies at the junction between adjacent layers in the crystal. The metal ion appears in a hexa‐aquo coordination, which is key to facilitating the crystallization of the protein.