Pup, a prokaryotic ubiquitin-like protein, is an intrinsically disordered protein. - Related Articles
Pup, a prokaryotic ubiquitin-like protein, is an intrinsically disordered protein.
Biochem J. 2009 Jul 7;
Authors: Liao S, Shang Q, Zhang X, Zhang J, Xu C, Tu X
Pup from Mycobacterium tuberculosis (Mtb) is the first ubiquitin-like protein identified in non-eukaryotic cells. Though different ubiquitin-like proteins from eukaryotes share low sequence similarity, their three-dimensional (3D) structures exhibit highly conserved typical ubiquitin-like fold. Interestingly, our studies reveal that Pup not only shares low sequence similarity but also presents a totally distinguished structure compared with other ubiquitin-like superfamily proteins. Diverse structure predictions combined with CD and NMR spectroscopic studies all demonstrate that Pup is an intrinsically disordered protein. Moreover, 1H-15N nuclear Overhauser effect (NOE) data and chemical shift index (CSI) analyses indicate that there is a residual secondary structure at the C-terminus of Pup. In Mtb, Mpa is the regulatory cap ATPase of proteasome that interacts with Pup and bring the substrates to the proteasome for degradation. Herein, surface plasmon resonance (SPR) and NMR perturbation studies imply the C-terminus of Pup ranging from residues 30 to 59 binds to Mpa most likely through a hydrophobic interface. In addition, phylogenetic analysis clearly shows that Pup family belongs to a unique and divergent evolution branch, suggesting it is the most ancient and deeply branched family among ubiquitin-like proteins. This might explain the structural distinction between Pup and other ubiquitin-like superfamily proteins.
PMID: 19580545 [PubMed - as supplied by publisher] [Tuberculosis Pulmonary]