Improving the resistance of a eukaryotic β-barrel protein to thermal and chemical perturbations

Copyright © 2011 Elsevier Ltd. All rights reserved..

β-Barrel membrane proteins have regular structures with extensive hydrogen-bond networks between their transmembrane (TM) β-strands, which stabilize their protein fold. Nevertheless, weakly stable TM regions, which are important for the protein function and interaction with other proteins, exist. Here, we report on the apparent stability of human Tom40A, a member of the "mitochondrial porin family" and main constituent of the mitochondrial protein-conducting channel TOM (translocase of the outer membrane). Using a physical interaction model, TmSIP, for β-barrel membrane proteins, we have identified three unfavorable β-strands in the TM domain of the protein. Substitution of key residues inside these strands with hydrophobic amino acids results in a decreased sensitivity of the protein to chemical and/or thermal denaturation. The apparent melting temperature observed when denatured at a rate of 1 °C per minute is shifted from 73 to 84 °C. Moreover, the sensitivity of the protein to denaturant agents is significantly lowered. Further, we find a reduced tendency for the mutated protein to form dimers. We propose that the identified weakly stable β-strands 1, 2 and 9 of human Tom40A play an important role in quaternary protein-protein interactions within the mammalian TOM machinery. Our results show that the use of empirical energy functions to model the apparent stability of β-barrel membrane proteins may be a useful tool in the field of nanopore bioengineering.

Medienart:

E-Artikel

Erscheinungsjahr:

2011

Erschienen:

2011

Enthalten in:

Zur Gesamtaufnahme - volume:413

Enthalten in:

Journal of molecular biology - 413(2011), 1 vom: 14. Okt., Seite 150-61

Sprache:

Englisch

Beteiligte Personen:

Gessmann, Dennis [VerfasserIn]
Mager, Frauke [VerfasserIn]
Naveed, Hammad [VerfasserIn]
Arnold, Thomas [VerfasserIn]
Weirich, Sara [VerfasserIn]
Linke, Dirk [VerfasserIn]
Liang, Jie [VerfasserIn]
Nussberger, Stephan [VerfasserIn]

Links:

Volltext

Themen:

Journal Article
Membrane Transport Proteins
Mitochondrial Precursor Protein Import Complex Proteins
Mitochondrial Proteins
Mutant Proteins
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
TOMM40 protein, human

Anmerkungen:

Date Completed 22.11.2011

Date Revised 03.12.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.jmb.2011.07.054

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM210690089