Thermodynamic characterization of variants of mesophilic cytochrome c and its thermophilic counterpart.


Thermal stability was measured for variants of cytochrome c-551 (PA c-551) from a mesophile, Pseudomonas aeruginosa, and a thermophilic counterpart, Hydrogenobacter thermophilus cytochrome c-552 (HT c-552), by differential scanning calorimetry (DSC) at pH 3.6. The mutated residues in PA c-551, selected with reference to the corresponding residues in HT c-552, were located in three spatially separated regions: region I, Phe7 to Ala/Val13 to Met; region II, Glu34 to Tyr/Phe43 to Tyr; and region III, Val78 to Ile. The thermodynamic parameters determined indicated that the mutations in regions I and III caused enhanced stability through not only enthalpic but also entropic contributions, which reflected improved packing of the side chains. Meanwhile, the mutated region II made enthalpic contributions to the stability through electrostatic interactions. The obtained differences in the Gibbs free energy changes of unfolding [Delta(DeltaG)] showed that the three regions contributed to the overall stability in an additive manner. HT c-552 had the smallest heat capacity change (DeltaC(P)), resulting in higher DeltaG values over a wide temperature range (0-100 degrees C), compared to the PA c-551 variants; this contributed to the highest stability of HT c-552. Our DSC measurement results, in conjunction with mutagenesis and structural studies on the homologous mesophilic and thermophilic cytochromes c, provided an extended thermodynamic view of protein stabilization. Study holds ProTherm entries: 15177, 15178, 15179, 15180, 15181, 15182, 15183, 15184, 15185, 15186, 15187, 15188, 15189, 15190, 15191, 15192, 15193, 15194 Extra Details: combined mutant; cytochrome c; differential scanning calorimetry (DSC); protein stability

Submission Details

ID: t3kUTbrn3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:45 p.m.

Version: 1

Publication Details
Uchiyama S;Hasegawa J;Tanimoto Y;Moriguchi H;Mizutani M;Igarashi Y;Sambongi Y;Kobayashi Y,Protein Eng. (2002) Thermodynamic characterization of variants of mesophilic cytochrome c and its thermophilic counterpart. PMID:12082163
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 UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Cytochrome c-552 P15452 CY552_HYDTT
100.0 Cytochrome c-551 P00099 CY551_PSEAE