5ms4
Kallikrein-related peptidase 8 leupeptin inhibitor complex
Structural highlights
FunctionKLK8_HUMAN Serine protease which is capable of degrading a number of proteins such as casein, fibrinogen, kininogen, fibronectin and collagen type IV. Also cleaves L1CAM in response to increased neural activity. Induces neurite outgrowth and fasciculation of cultured hippocampal neurons. Plays a role in the formation and maturation of orphan and small synaptic boutons in the Schaffer-collateral pathway, regulates Schaffer-collateral long-term potentiation in the hippocampus and is required for memory acquisition and synaptic plasticity. Involved in skin desquamation and keratinocyte proliferation. Plays a role in the secondary phase of pathogenesis following spinal cord injury.[1] Publication Abstract from PubMedHuman KLK8/neuropsin, a kallikrein-related serine peptidase, is mostly expressed in skin and the hippocampus regions of the brain, where it regulates memory formation by synaptic remodeling. Substrate profiles of recombinant KLK8 were analyzed with positional scanning using fluorogenic tetrapeptides and the proteomic PICS approach, which revealed the prime side specificity. Enzyme kinetics with optimized substrates showed stimulation by Ca(2+) and inhibition by Zn(2+), which are physiological regulators. Crystal structures of KLK8 with a ligand-free active site and with the inhibitor leupeptin explain the subsite specificity and display Ca(2+) bound to the 75-loop. The variants D70K and H99A confirmed the antagonistic role of the cation binding sites. Molecular docking and dynamics calculations provided insights in substrate binding and the dual regulation of activity by Ca(2+) and Zn(2+), which are important in neuron and skin physiology. Both cations participate in the allosteric surface loop network present in related serine proteases. A comparison of the positional scanning data with substrates from brain suggests an adaptive recognition by KLK8, based on the tertiary structures of its targets. These combined findings provide a comprehensive picture of the molecular mechanisms underlying the enzyme activity of KLK8. Structural determinants of specificity and regulation of activity in the allosteric loop network of human KLK8/neuropsin.,Debela M, Magdolen V, Skala W, Elsasser B, Schneider EL, Craik CS, Biniossek ML, Schilling O, Bode W, Brandstetter H, Goettig P Sci Rep. 2018 Jul 16;8(1):10705. doi: 10.1038/s41598-018-29058-6. PMID:30013126[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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