The role of retinal in the thermal stability of the purple membrane.


Abstract

Differential scanning calorimetry demonstrates that the bleached form of the purple membrane does not possess any measurable thermal transition in water, up to 105 degrees C, whereas in 0.1 M phosphate pH 7.5 it shows a transition at about 82 degrees C, with an enthalpy of 110 kJ/mol. In the latter medium, the native membrane shows the main transition at 97 degrees C, with an enthalpy of 390 kJ/mol. The reduced form of the purple membrane shows two small transitions in water, as well as in 0.1 M phosphate, which do not seem to be related to the main thermal transition of the native membrane. Fourier-transform infrared spectra in D2O show that the two modified samples, as well as the native one, undergo similar secondary structural changes upon thermal denaturation. These changes appear to extend through a wide temperature range for both modified forms, particularly for the bleached one. The results suggest that the main thermal transition in the purple membrane is due to a cooperative conformational change involving the disruption of the network of electrostatic and hydrogen-bonding interactions which originate from the protonated Schiff base. In the two modified membranes, these conformational changes appear to proceed smoothly through a rather low or non-cooperative process. The thermal behaviour of the bleached membrane in water resembles that of the molten globule state described for several globular proteins. Study holds ProTherm entries: 7160, 7161, 7162 Extra Details: molten globule state

Submission Details

ID: ETsL5q6n3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:33 p.m.

Version: 1

Publication Details
Cladera J;Galisteo ML;Sabés M;Mateo PL;Padrós E,Eur. J. Biochem. (1992) The role of retinal in the thermal stability of the purple membrane. PMID:1633811
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