Format

Send to

Choose Destination
Protein Sci. 1998 Nov;7(11):2384-90.

The interaction between the chaperone SecB and its ligands: evidence for multiple subsites for binding.

Author information

1
Department of Biochemistry and Biophysics, Washington State University, Pullman 99164-4660, USA.

Abstract

The chaperone protein SecB is dedicated to the facilitation of export of proteins from the cytoplasm to the periplasm and outer membrane of Escherichia coli. It functions to bind and deliver precursors of exported proteins to the membrane-associated translocation apparatus before the precursors fold into their native stable structures. The binding to SecB is characterized by a high selectivity for ligands having nonnative structure but a low specificity for consensus in sequence among the ligands. A model previously presented (Randall LL, Hardy SJS, 1995, Trends Biochem Sci 20:65-69) to rationalize the ability of SecB to distinguish between the native and nonnative states of a polypeptide proposes that the SecB tetramer contains two types of subsites for ligand binding: one kind that would interact with extended flexible stretches of polypeptides and the other with hydrophobic regions. Here we have used titration calorimetry, analytical ultracentrifugation, and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to obtain evidence that such distinguishable subsites exist.

PMID:
9828004
PMCID:
PMC2143860
DOI:
10.1002/pro.5560071115
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center