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Cryo-EM Structure of a Molluscan Hemocyanin Suggests Its Allosteric Mechanism
- Source :
- Structure. 21:604-613
- Publication Year :
- 2013
- Publisher :
- Elsevier BV, 2013.
-
Abstract
- Summary Hemocyanins are responsible for transporting O 2 in the arthropod and molluscan hemolymph. Haliotis diversicolor molluscan hemocyanin isoform 1 (HdH1) is an 8 MDa oligomer. Each subunit is made up of eight functional units (FUs). Each FU contains two Cu ions, which can reversibly bind an oxygen molecule. Here, we report a 4.5 A cryo-EM structure of HdH1. The structure clearly shows ten asymmetric units arranged with D5 symmetry. Each asymmetric unit contains two structurally distinct but chemically identical subunits. The map is sufficiently resolved to trace the entire subunit Cα backbone and to visualize densities corresponding to some large side chains, Cu ion pairs, and interaction networks of adjacent subunits. A FU topology path intertwining between the two subunits of the asymmetric unit is unambiguously determined. Our observations suggest a structural mechanism for the stability of the entire hemocyanin didecamer and 20 "communication clusters" across asymmetric units responsible for its allosteric property upon oxygen binding.
- Subjects :
- Models, Molecular
Molecular model
Protein Conformation
Stereochemistry
medicine.medical_treatment
Protein subunit
Gastropoda
Molecular Sequence Data
Allosteric regulation
02 engineering and technology
Biology
Oligomer
Article
03 medical and health sciences
chemistry.chemical_compound
Allosteric Regulation
Structural Biology
medicine
Animals
Molecule
Molecular Biology
030304 developmental biology
0303 health sciences
Base Sequence
Cryoelectron Microscopy
Oxygen transport
Hemocyanin
Sequence Analysis, DNA
021001 nanoscience & nanotechnology
Molecular biology
Protein Subunits
chemistry
Hemocyanins
0210 nano-technology
Copper
Oxygen binding
Subjects
Details
- ISSN :
- 09692126
- Volume :
- 21
- Database :
- OpenAIRE
- Journal :
- Structure
- Accession number :
- edsair.doi.dedup.....e05f8491c494bfe6ae8de91fb6774e22