Scanning calorimetry and Fourier-transform infrared studies into the thermal stability of cleaved bacteriorhodopsin systems.


Abstract

Differential scanning calorimetry and Fourier-transform infrared spectroscopy have been used to characterize the thermal stability of bacteriorhodopsin (BR) cleaved within different loops connecting the helical rods. The results are compared to those of the native protein. We show that the denaturation temperature and enthalpy of BR cleaved at peptide bond 71-72 or 155-156 are lower than those of the intact protein, and that these values become even lower for the BR cleaved at both peptide bonds. The effect of cleavage on the denaturation temperature and enthalpy values seems to be additive as has been previously suggested [Khan, T. W., Sturtevant, J. M., & Engelman, D. M. (1992) Biochemistry 31, 8829]. The thermal denaturation of all the samples was irreversible and scan-rate dependent. When cleaved at the 71-72 bond BR follows quantitatively the predictions of the two-state kinetic model at pH 9.5, with an activation energy of 374 kJ/mol, similar to that of native BR. Calorimetry experiments with different populations of intact and cleaved BR provide direct evidence for some intermolecular cooperativity upon denaturation. The denatured samples maintain a large proportion of alpha helices and beta structure, a fact which seems to be related to their low denaturation enthalpy as compared to that of water-soluble, globular proteins. Study holds ProTherm entries: 4873, 4874 Extra Details:

Submission Details

ID: nsnwHbuH4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:27 p.m.

Version: 1

Publication Details
Azuaga AI;Sepulcre F;PadrĂ³s E;Mateo PL,Biochemistry (1996) Scanning calorimetry and Fourier-transform infrared studies into the thermal stability of cleaved bacteriorhodopsin systems. PMID:8973208
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1AP9 1997-07-26T00:00:00+0000 2.35 X-RAY STRUCTURE OF BACTERIORHODOPSIN FROM MICROCRYSTALS GROWN IN LIPIDIC CUBIC PHASES
1AT9 1997-08-20T00:00:00+0000 3.0 STRUCTURE OF BACTERIORHODOPSIN AT 3.0 ANGSTROM DETERMINED BY ELECTRON CRYSTALLOGRAPHY
1BCT 1993-07-07T00:00:00+0000 0 THREE-DIMENSIONAL STRUCTURE OF PROTEOLYTIC FRAGMENT 163-231 OF BACTERIOOPSIN DETERMINED FROM NUCLEAR MAGNETIC RESONANCE DATA IN SOLUTION
1BHA 1993-10-11T00:00:00+0000 0 THREE-DIMENSIONAL STRUCTURE OF (1-71) BACTERIOOPSIN SOLUBILIZED IN METHANOL-CHLOROFORM AND SDS MICELLES DETERMINED BY 15N-1H HETERONUCLEAR NMR SPECTROSCOPY
1BHB 1993-10-11T00:00:00+0000 0 Three-dimensional structure of (1-71) bacterioopsin solubilized in methanol-chloroform and SDS micelles determined by 15N-1H heteronuclear NMR spectroscopy
1BM1 1998-07-28T00:00:00+0000 3.5 CRYSTAL STRUCTURE OF BACTERIORHODOPSIN IN THE LIGHT-ADAPTED STATE
1BRD 1990-05-23T00:00:00+0000 3.5 Model for the structure of Bacteriorhodopsin based on high-resolution Electron Cryo-microscopy
1BRR 1998-07-28T00:00:00+0000 2.9 X-RAY STRUCTURE OF THE BACTERIORHODOPSIN TRIMER/LIPID COMPLEX
1BRX 1998-05-28T00:00:00+0000 2.3 BACTERIORHODOPSIN/LIPID COMPLEX
1C3W 1999-07-28T00:00:00+0000 1.55 BACTERIORHODOPSIN/LIPID COMPLEX AT 1.55 A RESOLUTION

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Bacteriorhodopsin P02945 BACR_HALSA