Human COA3 Is an Oligomeric Highly Flexible Protein in Solution

The assembly of the protein complex of cytochrome c oxidase (COX), which participates in the mitochondrial respiratory chain, requires a large number of accessory proteins (the so-called assembly factors). Human COX assembly factor 3 (hCOA3), also known as MITRAC12 or coiled-coil domain-containing protein 56 (CCDC56), interacts with the first subunit protein of COX to form its catalytic core and promotes its assemblage with the other units. Therefore, hCOA3 is involved in COX biogenesis in humans and can be exploited as a drug target in patients with mitochondrial dysfunctions. However, to be considered a molecular target, its structure and conformational stability must first be elucidated. We have embarked on the description of such features by using spectroscopic and hydrodynamic techniques, in aqueous solution and in the presence of detergents, together with computational methods. Our results show that hCOA3 is an oligomeric protein, forming aggregates of different molecular masses in aqueous solution. Moreover, on the basis of fluorescence and circular dichroism results, the protein has (i) its unique tryptophan partially shielded from solvent and (ii) a relatively high percentage of secondary structure. However, this structure is highly flexible and does not involve hydrogen bonding. Experiments in the presence of detergents suggest a slightly higher content of nonrigid helical structure. Theoretical results, based on studies of the primary structure of the protein, further support the idea that hCOA3 is a disordered protein. We suggest that the flexibility of hCOA3 is crucial for its interaction with other proteins to favor mitochondrial protein translocation and assembly of proteins involved in the respiratory chain.

Medienart:

E-Artikel

Erscheinungsjahr:

2016

Erschienen:

2016

Enthalten in:

Zur Gesamtaufnahme - volume:55

Enthalten in:

Biochemistry - 55(2016), 45 vom: 15. Nov., Seite 6209-6220

Sprache:

Englisch

Beteiligte Personen:

Neira, José L [VerfasserIn]
Martínez-Rodríguez, Sergio [VerfasserIn]
Hernández-Cifre, José G [VerfasserIn]
Cámara-Artigas, Ana [VerfasserIn]
Clemente, Paula [VerfasserIn]
Peralta, Susana [VerfasserIn]
Fernández-Moreno, Miguel Ángel [VerfasserIn]
Garesse, Rafael [VerfasserIn]
García de la Torre, José [VerfasserIn]
Rizzuti, Bruno [VerfasserIn]

Themen:

368GB5141J
COA3 protein, human
EC 1.9.3.1
Electron Transport Complex IV
Intrinsically Disordered Proteins
Journal Article
Membrane Proteins
Mitochondrial Proteins
Protein Aggregates
Protein Subunits
Sodium Dodecyl Sulfate
Solutions

Anmerkungen:

Date Completed 22.05.2017

Date Revised 26.02.2021

published: Print-Electronic

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM265740142