Volume and compressibility changes accompanying thermally-induced native-to-unfolded and molten globule-to-unfolded transitions of cytochrome c: a high pressure study.


Abstract

We have measured the transition temperatures, T(M), and van't Hoff enthalpies, DeltaH(M), of the thermally induced native-to-unfolded (N-to-U) and molten globule-to-unfolded (MG-to-U) transitions of cytochrome c at pressures between 50 and 2200 bar. We have used the pressure dependence of T(M) to evaluate the changes in volume, Delta(v), accompanying each protein transition event as a function of temperature and pressure. From analysis of the temperature and pressure dependences of Delta(v), we have additionally calculated the changes in expansibility, Delta(e), and isothermal compressibility, Delta(k)(T), associated with the thermally induced conformational transitions of cytochrome c. Specifically, if extrapolated to 25 degrees C, the native-to-unfolded (N-to-U) transition is accompanied by changes in volume, Delta(v), expansibility, Delta(e), and isothermal compressibility, Delta(k)(T), of -(5 +/- 3) x 10(-3) cm(3) g(-1), (1.8 +/- 0.3) x 10(-4) cm(3) g(-1) K(-1), and approximately 0 cm(3) g(-1) bar(-1), respectively. The molten globule-to-unfolded (MG-to-U) transition is accompanied by changes in volume, Delta(v), and isothermal compressibility, Delta(k)(T), of -(2.9 +/- 0.3) x 10(-3) cm(3) g(-1) at 40 degrees C and -(1.9 +/- 0.3) x 10(-6) cm(3) g(-1) bar(-1) at 35 degrees C, respectively. By comparing the volumetric properties of the N-to-U and N-to-MG transitions of cytochrome c, we have estimated the properties of the native-to-molten globule (N-to-MG) transition. For the latter transition, the changes in volume, Delta(v), and isothermal compressibility, Delta(k)(T), are approximately 0 cm(3) g(-1) at 40 degrees C and 1.9 cm(3) g(-1) bar(-1) at 35 degrees C, respectively. Our estimate for the change in expansibility, Delta(e), upon the N-to-MG is negative and equal to -(5 +/- 3) x 10(-4) cm(3) g(-1) K(-1). This finding contrasts with the results of previous studies all of which report positive changes in expansibility associated with protein denaturation. In general, our volumetric data permit us to assess the combined effect of temperature and pressure on the stability of various conformational states of cytochrome c. Study holds ProTherm entries: 16498, 16499, 16500, 16501, 16502, 16503, 16504, 16505, 16506, 16507, 16508, 16509, 16510, 16511, 16512, 16513, 16514, 16515, 16516, 16517, 16518, 16519, 16520, 16521, 16522, 16523, 16524, 16525, 16526, 16527, 16528, 16529, 16530, 16531, 16532, 16533, 16534, 16535, 16536, 16537, 16538, 16539, 16540, 16541, 16542, 16543, 16544, 16545, 16546, 16547 Extra Details: at pressure 50 bar pressure dependence; molten globule; isothermal compressibility; expansibility

Submission Details

ID: AkVdhPbD

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:48 p.m.

Version: 1

Publication Details
Dubins DN;Filfil R;Macgregor RB;Chalikian TV,Biochemistry (2003) Volume and compressibility changes accompanying thermally-induced native-to-unfolded and molten globule-to-unfolded transitions of cytochrome c: a high pressure study. PMID:12873126
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
1KTD 2002-01-15T00:00:00+0000 2.4 CRYSTAL STRUCTURE OF CLASS II MHC MOLECULE IEK BOUND TO PIGEON CYTOCHROME C PEPTIDE
2B4Z 2005-09-27T00:00:00+0000 1.5 Crystal structure of cytochrome C from bovine heart at 1.5 A resolution.
2YBB 2011-03-02T00:00:00+0000 19.0 Fitted model for bovine mitochondrial supercomplex I1III2IV1 by single particle cryo-EM (EMD-1876)
3J2T 2012-12-23T00:00:00+0000 9.5 An improved model of the human apoptosome
5C0Z 2015-06-12T00:00:00+0000 1.12 The structure of oxidized rat cytochrome c at 1.13 angstroms resolution
5C9M 2015-06-28T00:00:00+0000 1.36 The structure of oxidized rat cytochrome c (T28A) at 1.362 angstroms resolution.
5DF5 2015-08-26T00:00:00+0000 1.3 The structure of oxidized rat cytochrome c (T28E) at 1.30 angstroms resolution.
5JUY 2016-05-10T00:00:00+0000 4.1 Active human apoptosome with procaspase-9
6FF5 2018-01-03T00:00:00+0000 1.74 X-ray structure of bovine heart cytochrome c at high ionic strength
6N1O 2018-11-09T00:00:00+0000 1.55 Oxidized rat cytochrome c mutant (S47E)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
91.3 Cytochrome c P00021 CYC_COLLI
92.2 Cytochrome c P00020 CYC_ANAPL
92.3 Cytochrome c P81280 CYC_ALLMI
90.5 Cytochrome c Q52V10 CYC_SAISC
93.3 Cytochrome c P00012 CYC_MIRLE
93.3 Cytochrome c Q52V09 CYC_CEPBA
93.3 Cytochrome c P00013 CYC_MINSC
93.3 Cytochrome c P00014 CYC_MACGI
94.3 Cytochrome c P00011 CYC_CANLF
94.3 Cytochrome c P62898 CYC_RAT
94.3 Cytochrome c P00008 CYC_RABIT
94.3 Cytochrome c P62897 CYC_MOUSE
95.2 Cytochrome c P68098 CYC_LAMGU
95.2 Cytochrome c P68100 CYC_ESCRO
95.2 Cytochrome c P68099 CYC_CAMDR
94.3 Cytochrome c P00007 CYC_HIPAM
97.1 Cytochrome c P62896 CYC_SHEEP
97.1 Cytochrome c P62895 CYC_PIG
97.1 Cytochrome c P62894 CYC_BOVIN
99.0 Cytochrome c P68096 CYC_EQUBU
99.0 Cytochrome c P68097 CYC_EQUAS
100.0 Cytochrome c P00004 CYC_HORSE
90.3 Cytochrome c B4USV4 CYC_OTOGA