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Philos Trans A Math Phys Eng Sci. 2016 Jul 28;374(2072). pii: 20150125. doi: 10.1098/rsta.2015.0125.

Exploring the in meso crystallization mechanism by characterizing the lipid mesophase microenvironment during the growth of single transmembrane α-helical peptide crystals.

Author information

1
Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3052, Australia Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia CSIRO Manufacturing Flagship, Private Bag 10, Clayton, Victoria 3169, Australia.
2
Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3052, Australia Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia.
3
CSIRO Manufacturing Flagship, 343 Royal Parade, Parkville, Victoria 3052, Australia.
4
Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia.
5
CSIRO Manufacturing Flagship, Private Bag 10, Clayton, Victoria 3169, Australia.
6
Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3052, Australia Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia.
7
Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3052, Australia Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia The ARC Dairy Innovation Hub, The University of Melbourne, Parkville, Victoria 3010, Australia.
8
CSIRO Manufacturing Flagship, Private Bag 10, Clayton, Victoria 3169, Australia School of Applied Sciences, College of Science, Engineering and Health, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia calum.drummond@rmit.edu.au.
9
School of Applied Sciences, College of Science, Engineering and Health, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia charlotte.conn@rmit.edu.au.

Abstract

The proposed mechanism for in meso crystallization of transmembrane proteins suggests that a protein or peptide is initially uniformly dispersed in the lipid self-assembly cubic phase but that crystals grow from a local lamellar phase, which acts as a conduit between the crystal and the bulk cubic phase. However, there is very limited experimental evidence for this theory. We have developed protocols to investigate the lipid mesophase microenvironment during crystal growth using standard procedures readily available in crystallography laboratories. This technique was used to characterize the microenvironment during crystal growth of the DAP12-TM peptide using synchrotron small angle X-ray scattering (SAXS) with a micro-sized X-ray beam. Crystal growth was found to occur from the gyroid cubic mesophase. For one in four crystals, a highly oriented local lamellar phase was observed, providing supporting evidence for the proposed mechanism for in meso crystallization. A new observation of this study was that we can differentiate diffraction peaks from crystals grown in meso, from peaks originating from the surrounding lipid matrix, potentially opening up the possibility of high-throughput SAXS analysis of in meso grown crystals.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

KEYWORDS:

DAP12; cubic mesophase; in meso crystallization; local lamellar phase

PMID:
27298442
PMCID:
PMC4920275
DOI:
10.1098/rsta.2015.0125
[Indexed for MEDLINE]
Free PMC Article

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