Structure of the periplasmic chaperone Skp suggests functional similarity with cytosolic chaperones despite differing architecture

Ingo P. Korndörfer, Monica K. Dommel, Arne Skerra

Research output: Contribution to journalArticlepeer-review

118 Scopus citations

Abstract

The 17-kDa protein (Skp) of Escherichia coli is a homotrimeric periplasmic chaperone for newly synthesized outer-membrane proteins. Here we present its X-ray structure at a resolution of 2.35 Å. Three hairpin-shaped aα-helical extensions reach out by ∼60 Å from a trimerization domain, which is composed of three intersubunit β-sheets that wind around a central axis. The α-helical extensions approach each other at their distal turns, resulting in a fold that resembles a 'three-pronged grasping forceps'. The overall shape of Skp is reminiscent of the cytosolic chaperone prefoldin, although it is based on a radically different topology. The peculiar architecture, with apparent plasticity of the prongs and distinct electrostatic and hydrophobic surface properties, supports the recently proposed biochemical mechanism of this chaperone: formation of a Skp3-Omp complex protects the outer membrane protein from aggregation during passage through the bacterial periplasm.

Original languageEnglish
Pages (from-to)1015-1020
Number of pages6
JournalNature Structural and Molecular Biology
Volume11
Issue number10
DOIs
StatePublished - Oct 2004

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