Chemical Evolution of De novo Designed Artificial Proteins Incorporating Biological Functions

The chemical evolution of four-α-helix bundle polypeptide to a flavoenzyme model was attempted by设计single-chain 53-peptides. The flavoenzyme models were examined for catalytic oxidation反应在aqueous解决方案，因为hydrophobic核心讨论要太过于激烈atalytic group,我们tested a series of alkan -sulfonates to enlarge it by forming mixed micelles The expandedhydrophobic core may more easily accommodate the hydrophobic substrate. the alkyl chain lengthlonger than dodecyl enhanced the oxidation of benzyl-NAH by a flavoenzyme model by about 6-fold.These results suggest the hydrophobic core in the bundle structure is useful to place thecatalytic groups and have the advantage of accommodating hydrophobic substrates. On the other hand，a porphyrin derivative was incorporated into a single-chained two-α-helix polypeptide containing 29amino acid residues the thiol side chain of Cys residue. the dimerized Fe(III)-porphyrin-linkedtwo -α- helix……More polypeptide was examined for the biomimetic peroxidase-like activity with H D22 - D2oi D22 - D2 or 3-chloroperbenzoic acid (mCPBA) as the oxidant. the ki D2cat - D2/ ki D2M - D2 value forthe oxidation by the polypeptide with mCPBA was increased by the polypeptide with 5000 times than that withH - D22 - D2O - D22 - D2.Thus我们demonstrated the possibility to utilize the hydrophobic core of the four-α-helix bundle structureevolve the artificial proteins chemically by de novo design to the artificial enzymes. Then，we chose a βαβ -structure as a polypeptide scaffold，因为the βα-unit is found in TIM barrel. in order to place a porphyrin ring in the hydrophobicspace in the folded structure，我们设计了一张单曲-chained 49-peptide applying the amphiphilic α-helix and β-strand motifs.Peroxidase-like oxidation activity of this polypeptide occurred specifically in the presence of LPOrather than H - D22 - D2 at low methanol content反映了hydrophobic inside was used as a binding site of the oxidant. We concludedthe de novo design of artificial proteins should be further polished to增强他们的catalyticactivities . less

The chemical evolution of four-α-helix bundle polypeptide to a flavoenzyme model was attempted by designing single-chain 53-peptides. The flavoenzyme models were examined for catalytic oxidation reaction in aqueous solution. Since the hydrophobic core seemed to be too tightly aggregated for atalytic group, we tested a series of alkane-sulfonates to enlarge it by forming mixed micelles. The expanded hydrophobic core may more easily accommodate the hydrophobic substrate. The alkyl chain length longer than dodecyl enhanced the oxidation of benzyl-NAH by a flavoenzyme model by about 6-fold. These results suggest that the hydrophobic core in the bundle structure is useful to place the catalytic groups and have the advantage of accommodating hydrophobic substrates. On the other hand, a porphyrin derivative was incorporated into a single-chained two-α-helix polypeptide containing 29 amino acid residues via the thiol side chain of Cys residue. The dimerized Fe(III)-porphyrin-linked two-α-helix … More polypeptide was examined for the biomimetic peroxidase-like activity with HィイD22ィエD2 OィイD22ィエD2 or 3-chloroperbenzoic acid (mCPBA) as the oxidant. The kィイD2catィエD2/KィイD2MィエD2 value for the oxidation by the polypeptide with mCPBA was increased by 5000 times than that with HィイD22ィエD2OィイD22ィエD2.Thus, we demonstrated the possibility to utilize the hydrophobic core of the four-α-helix bundle structure to evolve the artificial proteins chemically by de novo design to the artificial enzymes. Then, we chose a βαβα-structure as a polypeptide scaffold, since the βα-unit is found in TIM barrel. In order to place a porphyrin ring in the hydrophobic space in the folded structure, we designed a single-chained 49-peptide applying the amphiphilic α-helix and β-strand motifs. Peroxidase-like oxidation activity of this polypeptide occurred specifically in the presence of LPO rather than HィイD22ィエD2 OィイD22ィエD2 at low methanol content, reflecting that the hydrophobic inside was used as a binding site of the oxidant. We concluded that the de novo design of artificial proteins should be further polished to enhance their catalytic activities. Less