Mesophilic cytochrome c(551) of Pseudomonas aeruginosa (PA c(551)) became as stable as its thermophilic counterpart, Hydrogenobacter thermophilus cytochrome c(552) (HT c(552)), through only five amino acid substitutions. The five residues, distributed in three spatially separated regions, were selected and mutated with reference to the corresponding residues in HT c(552) through careful structure comparison. Thermodynamic analysis indicated that the stability of the quintuple mutant of PA c(551) could be partly attained through an enthalpic factor. The solution structure of the mutant showed that, as in HT c(552), there were tighter side chain packings in the mutated regions. Furthermore, the mutant had an increased total accessible surface area, resulting in great negative hydration free energy. Our results provide a novel example of protein stabilization in that limited amino acid substitutions can confer the overall stability of a natural highly thermophilic protein upon a mesophilic molecule. Study holds ProTherm entries: 9769, 9770, 9771, 9772, 9773, 9774, 14512, 14513 Extra Details: mesophilic; thermophilic; structure comparison; quintuple mutant;,side chain packings; hydration free energy
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:38 p.m.
|Number of data points||18|
|Proteins||Cytochrome c-552 ; Cytochrome c-551 ; Cytochrome c-551 ; Cytochrome c-552 ; Cytochrome c-551|
|Assays/Quantities/Protocols||Experimental Assay: dCp temp:47.3 C, ionic:-: - ; Experimental Assay: ddG ; Experimental Assay: dCp ionic:: ; Experimental Assay: dHcal ; Experimental Assay: Tm ; Experimental Assay: Cm ; Derived Quantity: dTm|
|Libraries||Mutations for sequence NEQLAKQKGCMACHDLKAKKVGPAYADVAKKYAGRKDAVDYLAGKIKKGGSGVWGSVPMPPQNVTDAEAKQLAQWILSIK ; Mutations for sequence EDPEVLFKNKGCVACHAIDTKMVGPAYKDVAAKFAGQAGAEAELAQRIKNGSQGVWGPIPMPPNAVSDDEAQTLAKWVLSQK|