Structure and kinetics of chemically cross-linked protein gels from small-angle X-ray scattering.
(2014) In Physical Chemistry Chemical Physics 16(9). p.4002-4011- Abstract
- Glutaraldehyde (GA) reacts with amino groups in proteins, forming intermolecular cross-links that, at sufficiently high protein concentration, can transform a protein solution into a gel. Although GA has been used as a cross-linking reagent for decades, neither the cross-linking chemistry nor the microstructure of the resulting protein gel have been clearly established. Here we use small-angle X-ray scattering (SAXS) to characterise the microstructure and structural kinetics of gels formed by cross-linking of pancreatic trypsin inhibitor, myoglobin or intestinal fatty acid-binding protein. By comparing the scattering from gels and dilute solutions, we extract the structure factor and the pair correlation function of the gels. The protein... (More)
- Glutaraldehyde (GA) reacts with amino groups in proteins, forming intermolecular cross-links that, at sufficiently high protein concentration, can transform a protein solution into a gel. Although GA has been used as a cross-linking reagent for decades, neither the cross-linking chemistry nor the microstructure of the resulting protein gel have been clearly established. Here we use small-angle X-ray scattering (SAXS) to characterise the microstructure and structural kinetics of gels formed by cross-linking of pancreatic trypsin inhibitor, myoglobin or intestinal fatty acid-binding protein. By comparing the scattering from gels and dilute solutions, we extract the structure factor and the pair correlation function of the gels. The protein gels are spatially heterogeneous, with dense clusters linked by sparse networks. Within the clusters, adjacent protein molecules are almost in contact, but the protein concentration in the cluster is much lower than in a crystal. At the ∼1 nm SAXS resolution, the native protein structure is unaffected by cross-linking. The cluster radius is in the range 10-50 nm, with the cluster size determined mainly by the availability of lysine amino groups on the protein surface. The development of structure in the gel, on time scales from minutes to hours, appears to obey first-order kinetics. Cross-linking is slower at acidic pH, where the population of amino groups in the reactive deprotonated form is low. These results support the use of cross-linked protein gels in NMR studies of protein dynamics and for modeling NMR relaxation in biological tissue. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4291007
- author
- Kaieda, Shuji LU ; Plivelic, Tomás LU and Halle, Bertil LU
- organization
- publishing date
- 2014
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 16
- issue
- 9
- pages
- 4002 - 4011
- publisher
- Royal Society of Chemistry
- external identifiers
-
- pmid:24445422
- wos:000330779900016
- scopus:84893656009
- pmid:24445422
- ISSN
- 1463-9084
- DOI
- 10.1039/c3cp54219j
- language
- English
- LU publication?
- yes
- id
- a74c7e2b-2339-406b-9798-005fa5ab5e6e (old id 4291007)
- date added to LUP
- 2016-04-01 10:51:42
- date last changed
- 2022-02-17 21:56:25
@article{a74c7e2b-2339-406b-9798-005fa5ab5e6e,
abstract = {{Glutaraldehyde (GA) reacts with amino groups in proteins, forming intermolecular cross-links that, at sufficiently high protein concentration, can transform a protein solution into a gel. Although GA has been used as a cross-linking reagent for decades, neither the cross-linking chemistry nor the microstructure of the resulting protein gel have been clearly established. Here we use small-angle X-ray scattering (SAXS) to characterise the microstructure and structural kinetics of gels formed by cross-linking of pancreatic trypsin inhibitor, myoglobin or intestinal fatty acid-binding protein. By comparing the scattering from gels and dilute solutions, we extract the structure factor and the pair correlation function of the gels. The protein gels are spatially heterogeneous, with dense clusters linked by sparse networks. Within the clusters, adjacent protein molecules are almost in contact, but the protein concentration in the cluster is much lower than in a crystal. At the ∼1 nm SAXS resolution, the native protein structure is unaffected by cross-linking. The cluster radius is in the range 10-50 nm, with the cluster size determined mainly by the availability of lysine amino groups on the protein surface. The development of structure in the gel, on time scales from minutes to hours, appears to obey first-order kinetics. Cross-linking is slower at acidic pH, where the population of amino groups in the reactive deprotonated form is low. These results support the use of cross-linked protein gels in NMR studies of protein dynamics and for modeling NMR relaxation in biological tissue.}},
author = {{Kaieda, Shuji and Plivelic, Tomás and Halle, Bertil}},
issn = {{1463-9084}},
language = {{eng}},
number = {{9}},
pages = {{4002--4011}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Structure and kinetics of chemically cross-linked protein gels from small-angle X-ray scattering.}},
url = {{http://dx.doi.org/10.1039/c3cp54219j}},
doi = {{10.1039/c3cp54219j}},
volume = {{16}},
year = {{2014}},
}