کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1928435 | 1050355 | 2014 | 5 صفحه PDF | دانلود رایگان |
• 3D structure of archaeal homolog of proteasome assembly chaperone PbaA was solved.
• The crystal structure reveals that PbaA forms a homopentamer.
• C-terminal segments with proteasome-activating motif are packed against the core.
• Homologous PbaA and PbaB have distinct tertiary and quaternary structures.
Formation of the eukaryotic proteasome is not a spontaneous process but a highly ordered process assisted by several assembly chaperones. In contrast, archaeal proteasome subunits can spontaneously assemble into an active form. Recent bioinformatic analysis identified the proteasome-assembly chaperone-like proteins, PbaA and PbaB, in archaea. Our previous study showed that the PbaB homotetramer functions as a proteasome activator through its tentacle-like C-terminal segments. However, a functional role of the other homolog PbaA has remained elusive. Here we determined the 2.25-Å resolution structure of PbaA, illustrating its disparate tertiary and quaternary structures compared with PbaB. PbaA forms a homopentamer in which the C-terminal segments, with a putative proteasome-activating motif, are packed against the core. These findings offer deeper insights into the molecular evolution relationships between the proteasome-assembly chaperones and the proteasome activators.
Journal: Biochemical and Biophysical Research Communications - Volume 453, Issue 3, 24 October 2014, Pages 493–497