Structure of the periplasmic chaperone Skp suggests functional similarity with cytosolic chaperones despite differing architecture.Korndorfer, I.P., Dommel, M.K., Skerra, A.
(2004) Nat.Struct.Mol.Biol. 11: 1015-1020
- PubMed: 15361861
- DOI: 10.1038/nsmb828
- PubMed Abstract:
- The periplasmic E. coli chaperone Skp is a trimer in solution: biophysical and preliminary crystallographic characterization
Schlapschy, M.,Dommel, M.K.,Hadian, K.,Fogarasi, M.,Korndoerfer, I.P.,Skerra, A.
() TO BE PUBLISHED --: --
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 A. Three hairpin-shaped alpha-helical extensions reach out ...
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 A. Three hairpin-shaped alpha-helical extensions reach out by approximately 60 A from a trimerization domain, which is composed of three intersubunit beta-sheets that wind around a central axis. The alpha-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 Skp(3)-Omp complex protects the outer membrane protein from aggregation during passage through the bacterial periplasm.
Lehrstuhl für Biologische Chemie, Technische Universität München, 85350 Freising-Weihenstephan, Germany.