4lzi

Characterization of Solanum tuberosum Multicystatin and Significance of Core Domains

spinqualitylabelsall models 4lzi, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4lzi is a 1 chain structure with sequence from Solanum tuberosum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CYTM_SOLTU Probably has a role in the plant's defense system. Publication Abstract from PubMed Potato (Solanum tuberosum) multicystatin (PMC) is a unique cystatin composed of eight repeating units, each capable of inhibiting cysteine proteases. PMC is a composite of several cystatins linked by trypsin-sensitive (serine protease) domains and undergoes transitions between soluble and crystalline forms. However, the significance and the regulatory mechanism or mechanisms governing these transitions are not clearly established. Here, we report the 2.2-A crystal structure of the trypsin-resistant PMC core consisting of the fifth, sixth, and seventh domains. The observed interdomain interaction explains PMC's resistance to trypsin and pH-dependent solubility/aggregation. Under acidic pH, weakening of the interdomain interactions exposes individual domains, resulting in not only depolymerization of the crystalline form but also exposure of cystatin domains for inhibition of cysteine proteases. This in turn allows serine protease-mediated fragmentation of PMC, producing approximately 10-kD domains with intact inhibitory capacity and faster diffusion, thus enhancing PMC's inhibitory ability toward cysteine proteases. The crystal structure, light-scattering experiments, isothermal titration calorimetry, and site-directed mutagenesis confirmed the critical role of pH and N-terminal residues in these dynamic transitions between monomer/polymer of PMC. Our data support a notion that the pH-dependent structural regulation of PMC has defense-related implications in tuber physiology via its ability to regulate protein catabolism. Characterization of Solanum tuberosum Multicystatin and the Significance of Core Domains.,Green AR, Nissen MS, Kumar GN, Knowles NR, Kang C Plant Cell. 2013 Dec;25(12):5043-52. doi: 10.1105/tpc.113.121004. Epub 2013 Dec, 20. PMID:24363310 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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