5d8n | pdb_00005d8n

Tomato leucine aminopeptidase mutant - K354E

spinqualitylabelsall models 5d8n, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5d8n is a 3 chain structure with sequence from Lycopersicon esculentum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, CL, EDO, MG Gene: LAPA1, LAP, LAP2 (Lycopersicon esculentum) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [AMPL1_SOLLC] Presumably involved in the processing and regular turnover of intracellular proteins. Publication Abstract from PubMed Tomato plants express acidic leucine aminopeptidase (LAP-A) in response to various environmental stressors. LAP-A not only functions as a peptidase for diverse peptide substrates, but also displays chaperone activity. A K354E mutation has been shown to abolish the peptidase activity but to enhance the chaperone activity of LAP-A. To better understand this moonlighting function of LAP-A, the crystal structure of the K354E mutant was determined at 2.15 A resolution. The structure reveals that the K354E mutation destabilizes an active-site loop and causes significant rearrangement of active-site residues, leading to loss of the catalytic metal-ion coordination required for the peptidase activity. Although the mutant was crystallized in the same hexameric form as wild-type LAP-A, gel-filtration chromatography revealed an apparent shift from the hexamer to lower-order oligomers for the K354E mutant, showing a mixture of monomers to trimers in solution. In addition, surface-probing assays indicated that the K354E mutant has more accessible hydrophobic areas than wild-type LAP-A. Consistently, computational thermodynamic estimations of the interfaces between LAP-A monomers suggest that increased exposure of hydrophobic surfaces occurs upon hexamer breakdown. These results suggest that the K354E mutation disrupts the active-site loop, which also contributes to the hexameric assembly, and destabilizes the hexamers, resulting in much greater hydrophobic areas accessible for efficient chaperone activity than in the wild-type LAP-A. Structural insights into chaperone-activity enhancement by a K354E mutation in tomato acidic leucine aminopeptidase.,DuPrez KT, Scranton MA, Walling LL, Fan L Acta Crystallogr D Struct Biol. 2016 May;72(Pt 5):694-702. doi:, 10.1107/S205979831600509X. Epub 2016 Apr 26. PMID:27139632 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminopeptidase 3D structures

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