The cap-binding protein eIF4E is the first in a chain of translation initiation factors that recruit 40S ribosomal subunits to the 5' end of eukaryotic mRNA. During cap-dependent translation, this protein binds to the 5'-terminal m(7)Gppp cap of the mRNA, as well as to the adaptor protein eIF4G. The latter then interacts with small ribosomal subunit-bound proteins, thereby promoting the mRNA recruitment process. Here, we show apo-eIF4E to be a protein that contains extensive unstructured regions, which are induced to fold upon recognition of the cap structure. Binding of eIF4G to apo-eIF4E likewise induces folding of the protein into a state that is similar to, but not identical with, that of cap-bound eIF4E. At the same time, binding of each of the binding partners of eIF4E modulates the kinetics with which it interacts with the other partner. We present structural, kinetic and mutagenesis data that allow us to deduce some of the detailed folding transitions that take place during the eIF4E interactions.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jmb.2005.12.034 | DOI Listing |
Nat Commun
January 2025
NMR Based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Aggregation intermediates play a pivotal role in the assembly of amyloid fibrils, which are central to the pathogenesis of neurodegenerative diseases. The structures of filamentous intermediates and mature fibrils are now efficiently determined by single-particle cryo-electron microscopy. By contrast, smaller pre-fibrillar α-Synuclein (αS) oligomers, crucial for initiating amyloidogenesis, remain largely uncharacterized.
View Article and Find Full Text PDFNat Chem
January 2025
Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark.
Amyloid fibrils are highly stable misfolded protein assemblies that play an important role in several neurodegenerative and systemic diseases. Although structural information of the amyloid state is now abundant, mechanistic details about the misfolding process remain elusive. Inspired by the Φ-value analysis of protein folding, we combined experiments and molecular simulations to resolve amino-acid contacts and determine the structure of the transition-state ensemble-the rate-limiting step-for fibril elongation of PI3K-SH3 amyloid fibrils.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Food Science and Engineering, Henan University of Technology, Zhengzhou, Henan Province, PR China. Electronic address:
The aim of this study was to investigate the mechanism of protein digestibility improvement by exploring the changes in structural characteristics of proteins in noodles with varying levels of mechanically activated starch. Therefore, different levels of mechanically activated wheat starch were mixed with refined wheat flour to produce noodles. Results showed that moderately mechanically activated starch could significantly improve protein digestibility and noodles containing 8.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Genetics and Developmental Biology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel. Electronic address:
During development, amniote vertebrate embryos transform from a flat sheet into a three-dimensional cylindrical form through ventral folding of the lateral sides of the sheet (the lateral plate [LP]) and their fusion in the ventral midline. Using a chick embryo slice system, we find that the flat stage is actually a poised balance of opposing dorsal and ventral elastic bending tensions. An intact extracellular matrix (ECM) is required for generating tension, as localized digestion of ECM dissipates tension, while removal of endoderm or ectoderm layers has no significant effect.
View Article and Find Full Text PDFExpert Rev Proteomics
January 2025
Department of Computer Science, Virginia Commonwealth University, Richmond, VA, USA.
Introduction: Molecular recognition features (MoRFs) are regions in protein sequences that undergo induced folding upon binding partner molecules. MoRFs are common in nature and can be predicted from sequences based on their distinctive sequence signatures.
Areas Covered: We overview 20 years of progress in the sequence-based prediction of MoRFs which resulted in the development of 25 predictors of MoRFs that interact with proteins, peptides, and lipids.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!