Atomic force microscopy reveals two conformations of the 20 S proteasome from fission yeast

Pawel Osmulski, Maria E Gaczynska

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The proteasome is a major cytosolic proteolytic complex, indispensable in eukaryotic cells. The barrel-shaped core of this enzyme, the 20 S proteasome, is built from 28 subunits forming four stacked rings. The two inner β-rings harbor active centers, whereas the two outer α-rings play a structural role. Crystal structure of the yeast 20 S particle showed that the entrance to the central channel was sealed. Because of this result, the path of substrates into the catalytic chamber has remained enigmatic. We have used tapping mode atomic force microscopy (AFM) in liquid to address the dynamic aspects of the 20 S proteasomes from fission yeast. We present here evidence that, when observed with AFM, the proteasome particles in top view position have either open or closed entrance to the central channel. The preferred conformation depends on the ligands present. Apparently, the addition of a substrate to the uninhibited proteasome shifts the equilibrium toward the open conformation. These results shed new light on the possible path of the substrate into the proteolytic chamber.

Original languageEnglish (US)
Pages (from-to)13171-13174
Number of pages4
JournalJournal of Biological Chemistry
Volume275
Issue number18
DOIs
StatePublished - May 5 2000

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Schizosaccharomyces
Atomic Force Microscopy
Proteasome Endopeptidase Complex
Yeast
Conformations
Atomic force microscopy
Substrates
Eukaryotic Cells
Ports and harbors
Yeasts
Crystal structure
Ligands
Liquids
Enzymes

ASJC Scopus subject areas

  • Biochemistry

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Atomic force microscopy reveals two conformations of the 20 S proteasome from fission yeast. / Osmulski, Pawel; Gaczynska, Maria E.

In: Journal of Biological Chemistry, Vol. 275, No. 18, 05.05.2000, p. 13171-13174.

Research output: Contribution to journalArticle

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