Insights into the role of protein molecule size and structure on interfacial properties using designed sequences

Dwyer, Mirjana Dimitrijev, He, Lizhong, James, Michael, Nelson, Andrew and Middelberg, Anton P. J. (2013) Insights into the role of protein molecule size and structure on interfacial properties using designed sequences. Journal of the Royal Society Interface, 10 80: . doi:10.1098/rsif.2012.0987


Author Dwyer, Mirjana Dimitrijev
He, Lizhong
James, Michael
Nelson, Andrew
Middelberg, Anton P. J.
Title Insights into the role of protein molecule size and structure on interfacial properties using designed sequences
Journal name Journal of the Royal Society Interface   Check publisher's open access policy
ISSN 1742-5689
1742-5662
Publication date 2013-03-01
Year available 2013
Sub-type Article (original research)
DOI 10.1098/rsif.2012.0987
Volume 10
Issue 80
Total pages 11
Place of publication London, United Kingdom
Publisher The Royal Society Publishing
Collection year 2014
Language eng
Abstract Mixtures of a large, structured protein with a smaller, unstructured component are inherently complex and hard to characterize at interfaces, leading to difficulties in understanding their interfacial behaviours and, therefore, formulation optimization. Here, we investigated interfacial properties of such a mixed system. Simplicity was achieved using designed sequences in which chemical differences had been eliminated to isolate the effect of molecular size and structure, namely a short unstructured peptide (DAMP1) and its longer structured protein concatamer (DAMP4). Interfacial tension measurements suggested that the size and bulk structuring of the larger molecule led to much slower adsorption kinetics. Neutron reflectometry at equilibrium revealed that both molecules adsorbed as a monolayer to the air-water interface (indicating unfolding of DAMP4 to give a chain of four connected DAMP1 molecules), with a concentration ratio equal to that in the bulk. This suggests the overall free energy of adsorption is equal despite differences in size and bulk structure. At small interfacial extensional strains, only molecule packing influenced the stress response. At larger strains, the effect of size became apparent, with DAMP4 registering a higher stress response and interfacial elasticity. When both componentswere present at the interface, most stress-dissipating movement was achieved by DAMP1. This work thus provides insights into the role of proteins' molecular size and structure on their interfacial properties, and the designed sequences introduced here can serve as effective tools for interfacial studies of proteins and polymers.
Keyword Protein
Peptide
Interface
Adsorption
Rheology
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 3 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Sun, 03 Mar 2013, 10:54:05 EST by System User on behalf of Centre for Biomolecular Engineering