Figure 1: Overview of MtbHUN dimer crystal structure.
From: Targeting Mycobacterium tuberculosis nucleoid-associated protein HU with structure-based inhibitors
(a) MtbHUN (residues 1–99) sequence with secondary structural elements; boxed sequence spanning residues 46–65 corresponds to the Prosite pattern PS00045, common to HU-IHF fold. (b) The crystal structure of MtbHUN dimer (protomer A coloured red; protomer B coloured teal) is shown in cartoon representation. In the dimer, helices α1, α2 assemble to form a four-helix bundle, while β2, β3, β4 and β5 define a DNA-binding β cleft. (c) MtbHUN dimer can be divided into two subdomains, S1 consisting of the four helix bundle and S2 containing the DNA-binding cleft. (d) The MtbHUN protomer dimerizes through the collapse of large hydrophobic patches at the interface. The surface profile of MtbHUN is generated with colour codes corresponding to surface electrostatic and hydrophobicity; Blue: positive, red: negative, orange: hydrophobic). (e) The base of S2, formed by anti-parallel β-sheet regions is stabilized by aromatic cluster of eight Phe rings (Phe47, 50, 79 and 85) from two protomers. 2Fo−Fc electron density map of aromatic cluster is contoured at 1.5σ level and displayed in stereo image representation with side chains as sticks.
