In:
Magnetic Resonance, Copernicus GmbH, Vol. 2, No. 1 ( 2021-06-04), p. 375-386
Abstract:
Abstract. Trigger factor (TF) is a highly conserved multi-domain molecular
chaperone that exerts its chaperone activity at the ribosomal tunnel exit
from which newly synthesized nascent chains emerge. TF also displays
promiscuous substrate binding for a large number of cytosolic proteins
independent of ribosome binding. We asked how TF recognizes a variety of
substrates while existing in a monomer–dimer equilibrium. Paramagnetic
nuclear magnetic resonance (NMR) and electron spin resonance (ESR)
spectroscopy were used to show that dimeric TF displays a high degree of
structural polymorphism in solution. A series of peptides has been generated
to quantify their TF binding affinities in relation with their sequence
compositions. The results confirmed a previous predication that TF
preferentially binds to peptide fragments that are rich in aromatic and
positively charged amino acids. NMR paramagnetic relaxation enhancement
analysis showed that TF utilizes multiple binding sites, located in the
chaperone domain and part of the prolyl trans–cis isomerization domain, to
interact with these peptides. Dimerization of TF effectively sequesters most
of the substrate binding sites, which are expected to become accessible upon
binding to the ribosome as a monomer. As TF lacks ATPase activity, which is
commonly used to trigger conformational changes within molecular chaperones
in action, the ribosome-binding-associated disassembly and conformational
rearrangements may be the underlying regulatory mechanism of its chaperone
activity.
Type of Medium:
Online Resource
ISSN:
2699-0016
DOI:
10.5194/mr-2-375-2021
DOI:
10.5194/mr-2-375-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2998533-X
