1. Biochemical and MALDI-TOF Mass Spectrometric Characterization of a Novel Native and Recombinant Cystine Knot Miniprotein from Solanum tuberosum subsp. andigenum cv. Churqueña.
- Author
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Cotabarren J, Tellechea ME, Tanco SM, Lorenzo J, Garcia-Pardo J, Avilés FX, and Obregón WD
- Subjects
- Amino Acid Sequence, Animals, Carboxypeptidases antagonists & inhibitors, Cattle, Cloning, Molecular, Cystine-Knot Miniproteins analysis, Cystine-Knot Miniproteins genetics, Cystine-Knot Miniproteins isolation & purification, Enzyme Activation drug effects, Kinetics, Plant Proteins analysis, Plant Proteins genetics, Plant Proteins isolation & purification, Protease Inhibitors analysis, Protease Inhibitors chemistry, Protease Inhibitors isolation & purification, Protease Inhibitors pharmacology, Sequence Analysis, DNA, Solanum tuberosum genetics, Solanum tuberosum metabolism, Swine, Cystine-Knot Miniproteins chemistry, Plant Proteins chemistry, Proteomics methods, Recombinant Proteins, Solanum tuberosum chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Abstract
Cystine-knot miniproteins (CKMPs) are an intriguing group of cysteine-rich molecules that combine the characteristics of proteins and peptides. Typically, CKMPs are fewer than 50 residues in length and share a characteristic knotted scaffold characterized by the presence of three intramolecular disulfide bonds that form the singular knotted structure. The knot scaffold confers on these proteins remarkable chemical, thermal, and proteolytic stability. Recently, CKMPs have emerged as a novel class of natural molecules with interesting pharmacological properties. In the present work, a novel cystine-knot metallocarboxypeptidase inhibitor (chuPCI) was isolated from tubers of Solanum tuberosum , subsp. andigenum cv. Churqueña. Our results demonstrated that chuPCI is a member of the A/B-type family of metallocarboxypeptidases inhibitors. chuPCI was expressed and characterized by a combination of biochemical and mass spectrometric techniques. Direct comparison of the MALDI-TOF mass spectra for the native and recombinant molecules allowed us to confirm the presence of four different forms of chuPCI in the tubers. The majority of such forms have a molecular weight of 4309 Da and contain a cyclized Gln in the N-terminus. The other three forms are derived from N-terminal and/or C-terminal proteolytic cleavages. Taken together, our results contribute to increase the current repertoire of natural CKMPs., Competing Interests: The authors declare no conflict of interest.
- Published
- 2018
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