The Grateful Infrared: Sequential Protein Structural Changes Resolved by Infrared Difference Spectroscopy

2016 ◽  
Vol 121 (2) ◽  
pp. 335-350 ◽  
Author(s):  
Tilman Kottke ◽  
Víctor A. Lórenz-Fonfría ◽  
Joachim Heberle
Keyword(s):  
Structural Changes ◽  
Difference Spectroscopy

Effect Of pH On The Stability And Conformation Of α-Thrombin

1981 ◽  
Author(s):  
German B Villanueva
Keyword(s):  
Chemical Modification ◽  
Structural Changes ◽  
Low Ph ◽  
Tryptophan Residue ◽  
Difference Spectroscopy ◽  
Compact Structure ◽  
Tyrosine Residues ◽  
Charge Interaction ◽  
The Stability ◽  
Peptide Region

It is known that storage at pH 6 stabilizes thrombin against inactivation. In order to determine whether structural changes accompany this stabilization, the conformation of human α-thrombin at pH 6.0 and 7.5 was investigated by chemical modification, solvent perturbation, UV difference spectroscopy and circular dichroism. It was shown that the CD spectra of α-thrombin at 230-200 nm peptide region were indistinguishable at two pH values indicating no difference in the secondary structure. However, differences were observed in the 320-250 nm aromatic region suggesting some changes in the microenvironment of the aromatic chromophores. Solvent perturbation in 20% ethylene glycol indicated 3.7 ± 0.5 Trp and 7.8 ± 0.5 Tyr were exposed to the solvent at pH 6.0 while 4.3 ± 0.4 Trp and 8.4 ± 0.5 Tyr were exposed at pH 7.5. Chemical modification of tryptophan residue by dimethyl(2-hydroxy- 5-nitrobenzyl)sulfonium bromide in a 100-fold molar excess of the reagent showed 3 reactive residues at pH 6.0 and 6 at pH 7.5. These results suggest that when thrombin is exposed to low pH, structural changes occur that decrease the relative degree of exposure of tryptophan and tyrosine residues. Furthermore, UV difference spectroscopy showed the development of a positive differential spectrum when thrombin at pH 6.0 was exposed to pH 7.5. From this study, it is concluded that the stability of thrombin at pH 6.0 is due to a more compact structure of the enzyme which is probably a result of reduced charge interaction at low pH.

Light-induced structural changes during early photo-intermediates of the eubacterial Cl−pump Fulvimarina rhodopsin observed by FTIR difference spectroscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 383-392 ◽  
Author(s):  
Faisal Hammad Mekky Koua ◽  
Hideki Kandori
Keyword(s):  
Marine Bacteria ◽  
Structural Changes ◽  
Difference Spectroscopy ◽  
Ftir Difference Spectroscopy

Fulvimarina pelagirhodopsin (FR) is a member of inward eubacterial light-activated Cl−translocating rhodopsins (ClR) that were found recently in marine bacteria.

scholarly journals Reductive activation and structural rearrangement in superoxide reductase: a combined infrared spectroscopic and computational study

2014 ◽  
Vol 16 (27) ◽  
pp. 14220-14230 ◽  
Author(s):  
M. Horch ◽  
A. F. Pinto ◽  
T. Utesch ◽  
M. A. Mroginski ◽  
C. V. Romão ◽  
...  
Keyword(s):  
Computational Methods ◽  
Structural Changes ◽  
Computational Study ◽  
Structural Rearrangement ◽  
Superoxide Reductase ◽  
Difference Spectroscopy ◽  
Combined Approach ◽  
Reductive Activation ◽  
Infrared Spectroscopic

Local and global structural changes that enable reductive activation of superoxide reductase are revealed by a combined approach of infrared difference spectroscopy and computational methods.

scholarly journals Resolving voltage-dependent structural changes of a membrane photoreceptor by surface-enhanced IR difference spectroscopy

2008 ◽  
Vol 105 (34) ◽  
pp. 12113-12117 ◽  
Author(s):  
X. Jiang ◽  
E. Zaitseva ◽  
M. Schmidt ◽  
F. Siebert ◽  
M. Engelhard ◽  
...  
Keyword(s):  
Structural Changes ◽  
Difference Spectroscopy ◽  
Surface Enhanced ◽  
Voltage Dependent

Reflectance-Difference Spectroscopy: a New Real-Time, In-Situ Analysis of MBE and OMCVD Growth Surfaces.

1988 ◽  
Vol 144 ◽  
Author(s):  
E. Colas ◽  
D.E. Aspnes ◽  
R. Bhat ◽  
A.A. Studna ◽  
M.A. Koza ◽  
...  
Keyword(s):  
Real Time ◽  
Structural Changes ◽  
Chemical Vapor ◽  
Growth Surface ◽  
Semiconductor Surface ◽  
Difference Spectroscopy ◽  
Kcal Mole ◽  
Large Size ◽  
Reflectance Difference Spectroscopy

ABSTRACTReflectance-difference spectroscopy (RDS) is a recently developed optical technique that allows to monitor chemical and structural changes at a growing semiconductor surface, in-situ and in real-time. This technique was applied recently to organometallic chemical vapor deposition (OMCVD) on a [100] GaAs growth surface. The results show that submonolayer coverage of reacted species can be followed by this technique, which provided unique insights into the microscopic growth mechanisms. The time, temperature and pressure dependences of surface coverage show that OMCVD growth is controlled by two basic processes with distinct activation energies, i.e. reversible chemisorption (at -26 kcal/mole), and decomposition (at 39 kcal/mole) of trimethylgallium (TMG) at surface lattice sites. The importance of reversible chemisorption, which is of an excluded-volume type, due to the large size of the TMG molecule, had been overlooked until now in the literature, where only one activation energy was used to describe growth kinetics.

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