Pre-transition effects mediate forces of assembly between transmembrane proteins

Journal Article · 23 February 2016 · eLife

DOI: https://doi.org/10.7554/eLife.13150.001 · OSTI ID:1414748

Katira, Sachi ^[1]; Mandadapu, Kranthi K. ^[2]; Vaikuntanathan, Suriyanarayanan ^[3]; Smit, Berend ^[4]; Chandler, David ^[1]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Dept. of Chemistry
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Dept. of Chemistry and Dept. of Chemical and Biomolecular Engineering
3. Univ. of Chicago, IL (United States). Dept. of Chemistry
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Dept. of Chemistry, Chemical Sciences Div.; Ecole Polytechnique Federale Lausanne (Switzlerland). Inst. des Sciences et Ingenierie Chimiques

We present a mechanism for a generic, powerful force of assembly and mobility for transmembrane proteins in lipid bilayers. This force is a pre-transition (or pre-melting) effect for the first-order transition between ordered and disordered phases in the membrane. Using large-scale molecular simulation, we show that a protein with hydrophobic thickness equal to that of the disordered phase embedded in an ordered bilayer stabilizes a microscopic order-disorder interface. The stiffness of that interface is finite. When two such proteins approach each other, they assemble because assembly reduces the net interfacial energy. Analogous to the hydrophobic effect, we refer to this phenomenon as the ‘orderphobic effect’. The effect is mediated by proximity to the order-disorder phase transition and the size and hydrophobic mismatch of the protein. Furthermore, the strength and range of forces arising from this effect are significantly larger than those that could arise from membrane elasticity for the membranes considered.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1414748
• Journal Information: eLife, Journal Name: eLife Journal Issue: February Vol. 5; ISSN 2050-084X
• Publisher: eLife Sciences Publications, Ltd.Copyright Statement
• Country of Publication: United States
• Language: English