Related Experiment Video
Updated: Jul 31, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
The active site structure of Thalassiosira weissflogii carbonic anhydrase 1
E H Cox1, G L McLendon, F M Morel
1Center for Environmental Bioinorganic Chemistry, Departments of Chemistry and Geosciences, Princeton University, Princeton, New Jersey 08544, USA.
Abstract:
X-ray absorption spectroscopy at the Zn K-edge indicates that the active site of the marine diatom Thalassiosira weissflogii carbonic anhydrase is strikingly similar to that of mammalian alpha-carbonic anhydrase enzymes. The zinc has three histidine ligands and a single water at 1.98 A. This is quite different from the beta-carbonic anhydrases of higher plants in which zinc is coordinated by two cysteine thiolates, one histidine, and a water molecule. The diatom carbonic anhydrase shows no significant sequence similarity with other carbonic anhydrases and may represent an example of convergent evolution at the molecular level.
Related Concept Videos
Enzymes
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme can...
ATP Synthase: Mechanism
ATP Synthase: Structure
ATP Driven Pumps II: P-type Pumps
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...

