The enzyme cleaves the Pro36-Pro37 bond of cysteine desulfurase (EC 2.8.1.7) removing three amino acid residues (Tyr-Ser-Pro) from the N-terminus after cleavage by mitochondrial processing peptidase.
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
The enzyme cleaves the Pro36-Pro37 bond of cysteine desulfurase (EC 2.8.1.7) removing three amino acid residues (Tyr-Ser-Pro) from the N-terminus after cleavage by mitochondrial processing peptidase.
substrate is likely processed by isoform Icp55 in two consecutive steps, in which Icp55 removes two destabilizing amino acids: first Phe and then in a second round of processing Tyr, resulting in the mature stable protein
the enzyme is involved in the processing pathway of yeast Nfs1 during its translocation into the mitochondrial matrix. Nfs1 from Saccharomyces cerevisiae undergoes two steps of proteolytic processing: first the mitochondrial processing peptidase (MPP) cleaves the precursor between Phe33 and Tyr34. Then Icp55 cleaves between Pro36 and Pro37 removing three amino acids residues (Tyr-Ser-Pro)
the enzyme is involved in the processing pathway of yeast Nfs1 during its translocation into the mitochondrial matrix. Nfs1 from Saccharomyces cerevisiae undergoes two steps of proteolytic processing: first the mitochondrial processing peptidase (MPP) cleaves the precursor between Phe33 and Tyr34. Then Icp55 cleaves between Pro36 and Pro37 removing three amino acids residues (Tyr-Ser-Pro). In the absence of Nfs1 processing by mitochondrial processing peptidase (MPP), the Nfs1 precursor is not cleaved by Icp55. The two prolines are of importance for the Icp55 cleavage reaction, because the replacement of a single proline changes the specificity to a new cleavage site without eliminating the cleavage reaction per se
Icp55 is critical for stabilization of the mitochondrial proteome. Icp55 removes an amino acid from a characteristic set of N-termini of preprotein intermediates generated by mitochondrial processing peptidase. Thereby Icp55 converts instable intermediates into stable proteins
global analysis of the N-proteome of yeast mitochondria, revealing the N-termini of 615 different proteins. The N-proteome of icp55DELTA mitochondria yielded proteins whose N-terminus differs by one residue from the mature N-terminus of wild-type mitochondria. Icp55 cleaves between the last amino acid of the presequence (tyrosine, leucine or phenylalanine) and the first residue of the mature protein, preferentially serine, alanine and threonine. The most frequent residue tyrosine is efficiently removed by Icp55 and thus is the best substrate of Icp55. The efficiency of cleavage is lower for leucine and phenylalanine
identification of 36 substrates utilizing charge-based fractional diagonal chromatography, enabling the differential quantitation of 1459 nonredundant N-terminal peptides between two Saccharomyces cerevisiae samples within 10 h of LC-MS, starting from only 50 microg of protein per condition and analyzing only 40% of the obtained fractions
the enzyme is active towards substrates with proline at P1' position (M-/-PA and Y-/-PA). Icp55 cleaves off bulky residues from N-termini of proteins. Active towards substrates Y-/-AA, Y-/-TA and Y-/-SA
the enzyme is involved in the processing pathway of yeast Nfs1 during its translocation into the mitochondrial matrix. Nfs1 from Saccharomyces cerevisiae undergoes two steps of proteolytic processing: first the mitochondrial processing peptidase (MPP) cleaves the precursor between Phe33 and Tyr34. Then Icp55 cleaves between Pro36 and Pro37 removing three amino acids residues (Tyr-Ser-Pro)
Icp55 is critical for stabilization of the mitochondrial proteome. Icp55 removes an amino acid from a characteristic set of N-termini of preprotein intermediates generated by mitochondrial processing peptidase. Thereby Icp55 converts instable intermediates into stable proteins
the activity of the enzyme depends critically on the presence of Mn2+. Reducing concentration of Mn2+ in reaction buffer from 1 mM to 0.006 mM reduces the activity of the enzyme by about 60%. Other divalent metal ions (Mg2+, Ca2+, Co2+, Ni2+ and Zn2+) fail to fully restore activity of the enzyme
Icp55 is critical for stabilization of the mitochondrial proteome. The cleavage by Icp55 stabilizes the substrate proteins by removing destabilizing amino acids
ICP55 is responsible for the removal of single N-terminal amino acids, and its action explained the -3 arginine processing motif of a number of mitochondrial proteins. ICP55 also removes single amino acids from mitochondrial proteins known to be cleaved at nonconserved arginine sites. Disruption of ICP55 alters mitochondrial protein stability in vitro and changes the protein turnover rate of selected proteins in vivo
2 * 52000, gel filtration, the enzyme exists in a rapid equilibrium between monomer and dimer. The dimer, not monomer, is the active species of the enzyme with loop dynamics at the dimer interface playing an important role in activity. Dynamics of Icp55 protein between two conformations of dimer are found to be important for activity of the enzyme
2 * 52000, gel filtration, the enzyme exists in a rapid equilibrium between monomer and dimer. The dimer, not monomer, is the active species of the enzyme with loop dynamics at the dimer interface playing an important role in activity. Dynamics of Icp55 protein between two conformations of dimer are found to be important for activity of the enzyme
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
free enzyme and in complex with inhibitor apstatin. The enzyme exists in a rapid equilibrium between monomer and dimer. The dimer, and not the monomer, is the active species with loop dynamics at the dimer interface playing an important role in activity
expression in Escherichia coli BL21(DE3). Full-length Icp55 construct can not be expressed in the soluble fraction. Two truncated versions, Icp55t1 with 42 amino acid N-terminal truncation and Icp55t2 with 57 amino acid N-terminal truncation, are successfully expressed in soluble forms. All activity assays for Icp55 are reported for Icp55t1 construct
identification of 36 substrates utilizing charge-based fractional diagonal chromatography, enabling the differential quantitation of 1459 nonredundant N-terminal peptides between two Saccharomyces cerevisiae samples within 10 h of LC-MS, starting from only 50 microg of protein per condition and analyzing only 40% of the obtained fractions
Novel highly sensitive, specific, and straightforward strategy for comprehensive N-terminal proteomics reveals unknown substrates of the mitochondrial peptidase Icp55