Probing Hemoglobin Confinement Inside Submicron Silica Tubes Using Synchrotron SAXS and Electrochemical Response

Overview

Journal Eur Biophys J

Specialty Biophysics

Date 2013 Jan 29

PMID 23354357

Authors

Soumit S Mandal

Brindha Nagarajan

H Amenitsch

Aninda J Bhattacharyya

Affiliations

Soon will be listed here.

Abstract

The configuration of hemoglobin in solution and confined inside silica nanotubes has been studied using synchrotron small angle X-ray scattering and electrochemical activity. Confinement inside submicron tubes of silica aid in preventing protein aggregation, which is vividly observed for unconfined protein in solution. The radius of gyration (R g) and size polydispersity (p) of confined hemoglobin was found to be lower than that in solution. This was also recently demonstrated in case of confined hemoglobin inside layered polymer capsules. The confined hemoglobin displayed a higher thermal stability with R g and p showing negligible changes in the temperature range 25-75 °C. The differences in configuration between the confined and unconfined protein were reflected in their electrochemical activity. Reversible electrochemical response (from cyclic voltammograms) obtained in case of the confined hemoglobin, in contrary to the observance of only a cathodic response for the unconfined protein, gave direct indication of the differences between the residences of the electroactive heme center in a different orientation compared to that in solution state. The confined Hb showed loss of reversibility only at higher temperatures. The electron transfer coefficient (α) and electron transfer rate constant (k s) were also different, providing additional evidence regarding structural differences between the unconfined and confined states of hemoglobin. Thus, absence of any adverse effects due to confinement of proteins inside the inorganic matrices such as silica nanotubes opens up new prospects for utilizing inorganic matrices as protein "encapsulators", as well as sensors at varying temperatures.

References

Peterson E, Leonard E, Foulke J, Oliff M, Salisbury R, Kim D . Folding myoglobin within a sol-gel glass: protein folding constrained to a small volume. Biophys J. 2008; 95(1):322-32. PMC: 2426629. DOI: 10.1529/biophysj.106.097428. View

Eggers D, Valentine J . Molecular confinement influences protein structure and enhances thermal protein stability. Protein Sci. 2001; 10(2):250-61. PMC: 2373941. DOI: 10.1110/ps.36201. View

Kapoor S, Mandal S, Bhattacharyya A . Structure and function of hemoglobin confined inside silica nanotubes. J Phys Chem B. 2009; 113(43):14189-95. DOI: 10.1021/jp9032707. View

Menaa B, Torres C, Herrero M, Rives V, Gilbert A, Eggers D . Protein adsorption onto organically modified silica glass leads to a different structure than sol-gel encapsulation. Biophys J. 2008; 95(8):L51-3. PMC: 2553140. DOI: 10.1529/biophysj.108.142182. View

Li X, Zheng W, Zhang L, Yu P, Lin Y, Su L . Effective electrochemical method for investigation of hemoglobin unfolding based on the redox property of heme groups at glassy carbon electrodes. Anal Chem. 2009; 81(20):8557-63. DOI: 10.1021/ac9015215. View

Fenimore P, Frauenfelder H, McMahon B, Young R . Bulk-solvent and hydration-shell fluctuations, similar to alpha- and beta-fluctuations in glasses, control protein motions and functions. Proc Natl Acad Sci U S A. 2004; 101(40):14408-13. PMC: 521939. DOI: 10.1073/pnas.0405573101. View

Burns A, Ow H, Wiesner U . Fluorescent core-shell silica nanoparticles: towards "Lab on a Particle" architectures for nanobiotechnology. Chem Soc Rev. 2006; 35(11):1028-42. DOI: 10.1039/b600562b. View

Conrad H, Mayer A, Thomas H, Vogel H . X-ray small-angle scattering from aqueous solutions of oxy-and deoxyhaemoglobin. J Mol Biol. 1969; 41(2):225-9. DOI: 10.1016/0022-2836(69)90387-8. View

Nakanishi K, Sakiyama T, Imamura K . On the adsorption of proteins on solid surfaces, a common but very complicated phenomenon. J Biosci Bioeng. 2005; 91(3):233-44. DOI: 10.1263/jbb.91.233. View

10.

Gao L, Gao Q . Hemoglobin niobate composite based biosensor for efficient determination of hydrogen peroxide in a broad pH range. Biosens Bioelectron. 2006; 22(7):1454-60. DOI: 10.1016/j.bios.2006.06.022. View

11.

Eggers D, Valentine J . Crowding and hydration effects on protein conformation: a study with sol-gel encapsulated proteins. J Mol Biol. 2001; 314(4):911-22. DOI: 10.1006/jmbi.2001.5166. View

12.

Lee C, Lang J, Yen C, Shih P, Lin T, Mou C . Enhancing stability and oxidation activity of cytochrome C by immobilization in the nanochannels of mesoporous aluminosilicates. J Phys Chem B. 2006; 109(25):12277-86. DOI: 10.1021/jp050535k. View

13.

Yi J, Thomas L, Richter-Addo G . Structure of human R-state aquomethemoglobin at 2.0 Å resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011; 67(Pt 6):647-51. PMC: 3107133. DOI: 10.1107/S1744309111012528. View

14.

Makowski L, Rodi D, Mandava S, Minh D, Gore D, Fischetti R . Molecular crowding inhibits intramolecular breathing motions in proteins. J Mol Biol. 2007; 375(2):529-46. PMC: 2219890. DOI: 10.1016/j.jmb.2007.07.075. View

15.

Mandal S, Bhaduri S, Amenitsch H, Bhattacharyya A . Synchrotron small-angle X-ray scattering studies of hemoglobin nonaggregation confined inside polymer capsules. J Phys Chem B. 2012; 116(32):9604-10. DOI: 10.1021/jp303596q. View

16.

Wang S, Chen T, Zhang Z, Shen X, Lu Z, Pang D . Direct electrochemistry and electrocatalysis of heme proteins entrapped in agarose hydrogel films in room-temperature ionic liquids. Langmuir. 2005; 21(20):9260-6. DOI: 10.1021/la050947k. View

17.

Sorin E, Pande V . Nanotube confinement denatures protein helices. J Am Chem Soc. 2006; 128(19):6316-7. DOI: 10.1021/ja060917j. View

18.

Tallury P, Payton K, Santra S . Silica-based multimodal/multifunctional nanoparticles for bioimaging and biosensing applications. Nanomedicine (Lond). 2008; 3(4):579-92. DOI: 10.2217/17435889.3.4.579. View

19.

Makowski L, Bardhan J, Gore D, Lal J, Mandava S, Park S . WAXS studies of the structural diversity of hemoglobin in solution. J Mol Biol. 2011; 408(5):909-21. PMC: 3081904. DOI: 10.1016/j.jmb.2011.02.062. View

20.

Moreira L, Poli A, Costa-Filho A, Imasato H . Pentacoordinate and hexacoordinate ferric hemes in acid medium: EPR, UV-Vis and CD studies of the giant extracellular hemoglobin of Glossoscolex paulistus. Biophys Chem. 2006; 124(1):62-72. DOI: 10.1016/j.bpc.2006.05.030. View