Related Experiment Video
Updated: Jan 27, 2026

Directed Assembly of Elastin-like Proteins into defined Supramolecular Structures and Cargo Encapsulation In Vitro
Published on: April 8, 2020
Structure and assembly of an augmented Sm-like archaeal protein 14-mer
Cameron Mura1, Martin Phillips, Anna Kozhukhovsky
1Howard Hughes Medical Institute, Molecular Biology Institute, and Department of Energy Institute for Genomics and Proteomics, 201 Boyer Hall Molecular Biology Institute, University of California, Box 951570, Los Angeles, CA 90095-1570, USA.
Abstract:
To better understand the roles of Sm proteins in forming the cores of many RNA-processing ribonucleoproteins, we determined the crystal structure of an atypical Sm-like archaeal protein (SmAP3) in which the conserved Sm domain is augmented by a previously uncharacterized, mixed alpha/beta C-terminal domain. The structure reveals an unexpected SmAP3 14-mer that is perforated by a cylindrical pore and is bound to 14 cadmium (Cd(2+)) ions. Individual heptamers adopt either "apical" or "equatorial" conformations that chelate Cd(2+) differently. SmAP3 forms supraheptameric oligomers (SmAP3)(n = 7,14,28) in solution, and assembly of the asymmetric 14-mer is modulated by differential divalent cation-binding in apical and equatorial subunits. Phylogenetic and sequence analyses substantiate SmAP3s as a unique subset of SmAPs. These results distinguish SmAP3s from other Sm proteins and provide a model for the structure and properties of Sm proteins >100 residues in length, e.g., several human Sm proteins.
More Related Videos
Related Concept Videos
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme...
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Protein Complex Assembly
Structural Protein Function
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to...
Structural Protein Function
Assembly of Complex Microtubule Structures

