scholarly journals Membrane Insertion and Topology of the Translocating Chain-Associating Membrane Protein (TRAM)

2011 ◽  
Vol 406 (4) ◽  
pp. 571-582 ◽  
Author(s):  
Silvia Tamborero ◽  
Marçal Vilar ◽  
Luis Martínez-Gil ◽  
Arthur E. Johnson ◽  
Ismael Mingarro
Keyword(s):  
Membrane Protein ◽  
Membrane Insertion ◽  
And Topology

scholarly journals Permissive sites and topology of an outer membrane protein with a reporter epitope.

1991 ◽  
Vol 173 (1) ◽  
pp. 262-275 ◽  
Author(s):  
A Charbit ◽  
J Ronco ◽  
V Michel ◽  
C Werts ◽  
M Hofnung
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
And Topology

scholarly journals Membrane insertion and topology of the translocon-associated protein (TRAP) gamma subunit

2017 ◽  
Vol 1859 (5) ◽  
pp. 903-909 ◽  
Author(s):  
Manuel Bañó-Polo ◽  
Carlos A. Martínez-Garay ◽  
Brayan Grau ◽  
Luis Martínez-Gil ◽  
Ismael Mingarro
Keyword(s):  
Membrane Insertion ◽  
Gamma Subunit ◽  
And Topology

Membrane insertion and topology of the amino-terminal domain TMD0 of multidrug-resistance associated protein 6 (MRP6)

FEBS Letters ◽  
2015 ◽  
Vol 589 (24PartB) ◽  
pp. 3921-3928 ◽  
Author(s):  
Flavia Cuviello ◽  
Åsa Tellgren-Roth ◽  
Patricia Lara ◽  
Frida Ruud Selin ◽  
Magnus Monné ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Membrane Insertion ◽  
Amino Terminal ◽  
Terminal Domain ◽  
And Topology ◽  
Amino Terminal Domain

scholarly journals YidC family members are involved in the membrane insertion, lateral integration, folding, and assembly of membrane proteins

2004 ◽  
Vol 166 (6) ◽  
pp. 769-774 ◽  
Author(s):  
Ross E. Dalbey ◽  
Andreas Kuhn
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Complexes ◽  
Family Members ◽  
Membrane Insertion ◽  
Conducting Channel ◽  
Energy Devices ◽  
Domains Of Life ◽  
Membrane Protein Complexes ◽  
Sensor Proteins

Members of the YidC family exist in all three domains of life, where they control the assembly of a large variety of membrane protein complexes that function as transporters, energy devices, or sensor proteins. Recent studies in bacteria have shown that YidC functions on its own as a membrane protein insertase independent of the Sec protein–conducting channel. YidC can also assist in the lateral integration and folding of membrane proteins that insert into the membrane via the Sec pathway.

scholarly journals Dynamic membrane topology in an unassembled membrane protein

2019 ◽  
Author(s):  
Maximilian Seurig ◽  
Moira Ek ◽  
Gunnar von Heijne ◽  
Nir Fluman
Keyword(s):  
Membrane Protein ◽  
Transmembrane Helix ◽  
Membrane Topology ◽  
Topological Dynamics ◽  
Membrane Insertion ◽  
Dynamic Membrane ◽  
Membrane Protein Topology ◽  
Small Multidrug Resistance ◽  
Kinetics Of

AbstractHelical membrane proteins constitute roughly a quarter of all proteomes and perform diverse biological functions. To avoid aggregation, they undergo cotranslational membrane insertion and are typically assumed to attain stable transmembrane topologies immediately upon insertion. To what extent post-translational changes in topology are possible in-vivo and how they may affect biogenesis is incompletely understood. Here, we show that monomeric forms of Small Multidrug Resistance (SMR) proteins display topological dynamics, where the N-terminal transmembrane helix equilibrates between membrane-inserted and non-inserted states. We characterize the kinetics of the process and show how the composition of the helix regulates the topological dynamics. We further show that topological dynamics is a property of the unassembled monomeric protein, as the N-terminal helix becomes fixed in a transmembrane disposition upon dimerization. Membrane protein topology can thus remain dynamic long after cotranslational membrane insertion, and can be regulated by later assembly processes.

scholarly journals Intra-helical salt bridge contribution to membrane protein insertion

2021 ◽  
Author(s):  
Gerard Duart ◽  
John Lamb ◽  
Arne Elofsson ◽  
Ismael Mingarro
Keyword(s):  
Amino Acids ◽  
Membrane Protein ◽  
Electrostatic Interactions ◽  
Salt Bridge ◽  
Protein Stabilization ◽  
Membrane Insertion ◽  
Salt Bridges ◽  
Protein Insertion

ABSTRACTSalt bridges between negatively (D, E) and positively charged (K, R, H) amino acids play an important role in protein stabilization. This has a more prevalent effect in membrane proteins where polar amino acids are exposed to a very hydrophobic environment. In transmembrane (TM) helices the presence of charged residues can hinder the insertion of the helices into the membrane. This can sometimes be avoided by TM region rearrangements after insertion, but it is also possible that the formation of salt bridges could decrease the cost of membrane integration. However, the presence of intra-helical salt bridges in TM domains and their effect on insertion has not been properly studied yet. In this work, we use an analytical pipeline to study the prevalence of charged pairs of amino acid residues in TM α-helices, which shows that potentially salt-bridge forming pairs are statistically over-represented. We then selected some candidates to experimentally determine the contribution of these electrostatic interactions to the translocon-assisted membrane insertion process. Using both in vitro and in vivo systems, we confirm the presence of intra-helical salt bridges in TM segments during biogenesis and determined that they contribute between 0.5-0.7 kcal/mol to the apparent free energy of membrane insertion (ΔGapp). Our observations suggest that salt bridge interactions can be stabilized during translocon-mediated insertion and thus could be relevant to consider for the future development of membrane protein prediction software.

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