Stabilization of mesophilic Allochromatium vinosum cytochrome c′ through specific mutations modeled by a thermophilic homologue

Abstract

AVCP cytochrome c' from mesophilic Allochromatium vinosum exhibits lower stability than a thermophilic counterpart, Hydrogenophilus thermoluteolus cytochrome c' (PHCP), in which the six specific amino acid residues that are not conserved in AVCP are responsible for its stability. Here we measured the stability of AVCP variants carrying these specific residues instead of the original AVCP ones. Among the six single AVCP variants, all of which formed a dimeric structure similar to that of the wild-type, three were successfully stabilized compared with the wild-type, while one showed lower stability than the wild-type. In addition, the most stabilized and destabilized AVCP variants could bind CO, similar to the wild-type. These results indicated that mesophilic AVCP could be stabilized through specific three mutations modeled by the thermophilic counterpart, PHCP, without changing the CO binding ability.

One fold, two functions: cytochrome P460 and cytochrome c′-β from the methanotroph Methylococcus capsulatus (Bath)

“…3b), indicating that the latter has a two-step transition during its thermal denaturation and more stable than the former. The unfolding transitions are much broader for McP460 and McCP-β as is typical for β-sheet proteins in comparison to those of cyts cp-α 31,32. We note for context that the optimum growth temperature of M. capsulatus (Bath) is 45 °C 33…”

Activity prediction of aminoquinoline drugs based on deep learning

“…Accurately weigh 0.4 mmol quinoline N‐oxide with analytical balance, add 0.8 mmol diethyl h‐ph, 0.5 mL carbon tetrachloride, and 2 equivalent potassium carbonate successively, and then add 0.25, 0.5, 0.75, 1, 1.5, and 1.75 N‐propylamine, respectively. Put it in 1 mL DMF solution and stir it at room temperature for 3 H. After that, separate and calculate the yield [42–44]. In this way, the best proportion of reactants is examined, and the reaction results are shown in the small scale.…”

Crystal structure of thermally stable homodimeric cytochrome c′-β from Thermus thermophilus

“…The mechanism of protein stabilization depends on specific amino-acid interactions such as the formation of hydrogen bonds and salt bridges, increased hydrophobicity and so on (Razvi & Scholtz, 2006). For instance, the monomeric cytochrome c 555 from the thermophilic Aquifex aeolicus is stabilized by an extra helix structure and interior hydrophobic interactions (Obuchi et al, 2009;Yamanaka et al, 2011), whereas the homodimeric cytochromes c 0 -from the moderately thermophilic Hydrogenophilus thermoluteolus and Thermochromatium tepidum are stabilized by amino-acid side-chain interactions at the homodimeric interface and around the heme (Yamane-Koshizawa et al, 2018;Fujii et al, 2021).…”