A new microperoxidase from Marinobacter hydrocarbonoclasticus

Area of Science:

• Biochemistry
• Protein Engineering
• Enzymology

Background:

• Microperoxidases are heme-containing peptides derived from cytochromes.
• Canonical microperoxidases possess a conserved CXXCH motif for heme binding.
• Proteinase K treatment of cytochrome c(552) is a method for microperoxidase generation.

Purpose of the Study:

• To prepare and characterize a novel microperoxidase (MMP-5) from Marinobacter hydrocarbonoclasticus.
• To investigate the structural, spectroscopic, and functional properties of MMP-5.
• To compare MMP-5 with previously reported microperoxidases.

Main Methods:

• Proteinase K digestion of cytochrome c(552) from Marinobacter hydrocarbonoclasticus.
• Spectroscopic analysis (UV-Vis) to determine electronic properties and heme coordination.
• Assays to evaluate peroxidatic activity in the presence of hydrogen peroxide.

Main Results:

• A novel microperoxidase, MMP-5, was successfully prepared, lacking the two intervening amino acid residues in the heme-binding motif.
• MMP-5 demonstrated increased solubility in aqueous solvents and 1-2 orders of magnitude higher monomeric stability compared to canonical microperoxidases.
• Spectroscopic studies revealed typical microperoxidase behavior with pH-dependent high-spin and low-spin heme states, and peroxidatic activity was confirmed.

Conclusions:

• The engineered heme-pentapeptide MMP-5 possesses unique structural features conferring enhanced stability and solubility.
• MMP-5 retains characteristic spectroscopic properties and functional peroxidatic activity.
• This novel microperoxidase represents a promising candidate for various biochemical and biotechnological applications.