Related Experiment Video
Updated: Mar 9, 2026
06:47
Author Spotlight: A Bicelle Crystallization Setup for ABC Transporter Membrane Proteins to Advance Drug Development
Published on: August 25, 2023
1.9K
Calcium Binding Dramatically Stabilizes an Ancestral Crystallin Fold in Tunicate βγ-Crystallin
Natalia Kozlyuk1, Suvrajit Sengupta1, Jan C Bierma2
1Department of Chemistry, University of California , Irvine, California 92697-2025, United States.
Biochemistry
|December 21, 2016
Summary
Tunicate βγ-crystallin strongly binds calcium ions (Ca²⁺), stabilizing the protein. This finding offers insights into the evolution of human βγ-crystallins and their lost Ca²⁺-binding ability.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Structural Biology
Background:
- Vertebrate βγ-crystallins are structural proteins in the eye lens.
- Ancestral proteins to vertebrate βγ-crystallins are calcium-binding proteins.
- Microbial βγ-crystallins exhibit calcium-binding-induced stabilization.
Purpose of the Study:
- To investigate the functional properties of tunicate (Ciona intestinalis) βγ-crystallin.
- To understand the evolutionary transition between calcium-binding proteins and structural crystallins.
- To explore the functional origin of the absence of calcium-binding sites in human βγ-crystallins.
Main Methods:
- Biochemical characterization of tunicate βγ-crystallin.
- Comparative analysis of βγ-crystallin binding sites across species.
- Structural and functional comparisons between tunicate and vertebrate crystallins.
Main Results:
- Tunicate βγ-crystallin exhibits strong calcium ion (Ca²⁺) binding.
- Ca²⁺ binding significantly stabilizes the tunicate βγ-crystallin structure.
- This stabilization effect mirrors that seen in microbial βγ-crystallins, but not vertebrates.
Conclusions:
- Tunicate βγ-crystallin serves as an intermediate model between ancestral calcium-binding proteins and vertebrate structural crystallins.
- The study provides a basis for understanding the evolutionary loss of Ca²⁺-binding in human βγ-crystallins.
- Comparative binding site analysis may elucidate the functional reasons for Ca²⁺-binding site absence in human crystallins.
More Related Videos
Related Concept Videos
01:16Calmodulin-dependent Signaling
6.8K
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
6.8K
01:25Structure of Cadherins
5.0K
The cadherins were one of the first cell adhesion molecules discovered; the term “cadherins” is based on their calcium-dependent adhering properties. The first cadherins discovered on the epithelial, neuronal, and placental cells were named E-cadherin, P-cadherin, and N-cadherin, respectively. These classical cadherins share sequence and structural similarities. Other cadherins, including those involved in cell signaling, are grouped into non-classical cadherins. This...
5.0K
01:49Conserved Binding Sites
5.3K
Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
5.3K
01:22Protein Folding
129.6K
Overview
129.6K
01:25Protein Folding
12.0K
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
12.0K
01:21Skeleton and Calcium Homeostasis
6.4K
Calcium is not only the most abundant mineral in bone but also the most abundant mineral in the human body. Calcium ions are needed for bone mineralization, tooth health, heart rate regulation and strength of contraction, blood coagulation, the contraction of smooth and skeletal muscle cells, and the regulation of nerve impulse conduction. The average calcium level in the blood is about 10 mg/dL. When the body cannot maintain this level, a person will experience hypo or hypercalcemia.
6.4K