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- Kmiec, Beata, et al.
(författare)
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Organellar oligopeptidase (OOP) provides a complementary pathway for targeting peptide degradation in mitochondria and chloroplasts
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:40, s. E3761-E3769
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Tidskriftsartikel (refereegranskat)abstract
- Both mitochondria and chloroplasts contain distinct proteolytic systems for precursor protein processing catalyzed by the mitochondrial and stromal processing peptidases and for the degradation of targeting peptides catalyzed by presequence protease. Here, we have identified and characterized a component of the organellar proteolytic systems in Arabidopsis thaliana, the organellar oligopeptidase, OOP (At5g65620). OOP belongs to the M3A family of peptide-degrading metalloproteases. Using two independent in vivo methods, we show that the protease is dually localized to mitochondria and chloroplasts. Furthermore, we localized the OPP homolog At5g10540 to the cytosol. Analysis of peptide degradation by OOP revealed substrate size restriction from 8 to 23 aa residues. Short mitochondrial targeting peptides (presequence of the ribosomal protein L29 and presequence of 1-aminocyclopropane-1-carboxylic acid deaminase 1) and N- and C-terminal fragments derived from the presequence of the ATPase beta subunit ranging in size from 11 to 20 aa could be degraded. MS analysis showed that OOP does not exhibit a strict cleavage pattern but shows a weak preference for hydrophobic residues (F/L) at the P1 position. The crystal structures of OOP, at 1.8-1.9 angstrom, exhibit an ellipsoidal shape consisting of two major domains enclosing the catalytic cavity of 3,000 angstrom(3). The structural and biochemical data suggest that the protein undergoes conformational changes to allow peptide binding and proteolysis. Our results demonstrate the complementary role of OOP in targeting-peptide degradation in mitochondria and chloroplasts.
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- Qundos, Ulrika, et al.
(författare)
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Analysis of plasma from prostate cancer patients links decreased carnosine dipeptidase 1 levels to lymph node metastasis
- 2014
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Ingår i: Translational Proteomics. - : Elsevier BV. - 2212-9634 .- 2212-9626. ; 2:1, s. 14-24
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for a better differentiation of aggressive tumors in prostate cancer to design a tailored treatment for each patient, preferably by a minimally invasive analysis of blood samples. In a previous study, we discovered a decrease of plasma levels of carnosine dipeptidase 1 (CNDP1) in association with aggressive prostate cancer. Now this relation has been investigated and characterized further by generating several new antibodies for extended analysis of CNDP1 in plasma. Multi-antibody sandwich assays were developed and applied to 1214 samples from two Swedish cohorts that confirmed decreased levels of CNDP1 in plasma from patients with advanced disease. Therein, data from CNDP1 assays allowed a better differentiation between tumor N stages than clinical tPSA, but did not when classifying T or M stages. Further investigations can now elucidate mechanisms behind decreasing levels of CNDP1 in plasma and primary in regards to lymph node metastasis.
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- Selao, Tiago Toscano, et al.
(författare)
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Identification of Chromatophore Membrane Protein Complexes Formed under Different Nitrogen Availability Conditions in Rhodospirillum rubrum
- 2011
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 10:6, s. 2703-2714
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Tidskriftsartikel (refereegranskat)abstract
- The chromatophore membrane of the photosynthetic diazotroph Rhodospirillum rubrum is of vital importance for a number of central processes, including nitrogen fixation. Using a novel amphiphile, we have identified protein complexes present under different nitrogen availability conditions by the use of two-dimensional Blue Native/SDS-PAGE and NSI-LC-LTQ-Orbitrap mass spectrometry. We have identified several membrane protein complexes, including components of the ATP synthase, reaction center, light harvesting, and NADH dehydrogenase complexes. Additionally, we have identified differentially expressed proteins, such as subunits of the succinate dehydrogenase complex and other TCA cycle enzymes that are usually found in the cytosol, thus hinting at a possible association to the membrane in response to nitrogen deficiency. We propose a redox sensing mechanism that can influence the membrane subproteome in response to nitrogen availability.
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