Mitochondrial intermediate peptidase: Expression in Escherichia coli and improvement of its enzymatic activity detection with FRET substrates

• Published in: Biochemical and biophysical research communications Vol. 391; no. 1; pp. 123 - 128
• Main Authors: Marcondes, Marcelo F., Torquato, Ricardo J.S., Assis, Diego M., Juliano, Maria A., Hayashi, Mirian A.F., Oliveira, Vitor
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2010
• Subjects: 60 APPLIED LIFE SCIENCES; Amino Acid Sequence; ANTIBODIES; Bacterial expression; CARBOXYLIC ACIDS; CLONING; DICHROISM; ENERGY TRANSFER; Enzymatic activity; ESCHERICHIA COLI; Escherichia coli - genetics; FLUORESCENCE; Fluorescence Resonance Energy Transfer; FRET substrate; Humans; ION EXCHANGE CHROMATOGRAPHY; Metalloendopeptidases - biosynthesis; Metalloendopeptidases - chemistry; Metalloendopeptidases - genetics; MITOCHONDRIA; Peptidase; Protease Inhibitors - chemistry; Protease Inhibitors - pharmacology; PROTEINS; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; RESINS; Substrate Specificity; SUBSTRATES; Mitochondria; Peptidase; Enzymatic activity; PMSF; E-64; FRET; FRET substrate; JA-2; Bacterial expression
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2009.11.014

In the present study, soluble, functionally-active, recombinant human mitochondrial intermediate peptidase (hMIP), a mitochondrial metalloendoprotease, was expressed in a prokaryotic system. The hMIP fusion protein, with a poly-His-tag (6× His), was obtained by cloning the coding region of hMIP cDNA into the pET-28a expression vector, which was then used to transform Escherichia coli BL21 (DE3) pLysS. After isolation and purification of the fusion protein by affinity chromatography using Ni–Sepharose resin, the protein was purified further using ion exchange chromatography with a Hi-trap resource Q column. The recombinant hMIP was characterized by Western blotting using three distinct antibodies, circular dichroism, and enzymatic assays that used the first FRET substrates developed for MIP and a series of protease inhibitors. The successful expression of enzymatically-active hMIP in addition to the FRET substrates will contribute greatly to the determination of substrate specificity of this protease and to the development of specific inhibitors that are essential for a better understanding of the role of this protease in mitochondrial functioning.