4ouh

Crystal structure of the FP domain of Human PI31 Proteasome Inhibitor

spinqualitylabelsall models 4ouh, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ouh is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PSMF1_HUMAN Plays an important role in control of proteasome function. Inhibits the hydrolysis of protein and peptide substrates by the 20S proteasome. Also inhibits the activation of the proteasome by the proteasome regulatory proteins PA700 and PA28. Publication Abstract from PubMed Fbxo7 and PI31 contain a conserved FP domain that mediates the homo-/hetero-dimerization of the proteins. The PI31 FP domain may also interact with the F-box motif in Fbxo7. The FP domain-mediated protein-protein interactions are important for the functions of Fbxo7 and PI31. The crystal structures of the Fbxo7 and PI31 FP domains were determined previously, showing that a C-terminal helix in the Fbxo7 FP domain was not present in the PI31 FP domain. Here, we determine the crystal structure of the PI31 FP domain using a longer protein construct. The structure is comparable to the Fbxo7 FP domain (including the C-terminal helix), indicating that the two FP domains share the same global fold. However, the FP domains also harbor their own characteristic structural features, mainly in the longest loop (which has a largely fixed conformation due to extensive hydrogen bonding and hydrophobic interactions) and the C-terminal end regions. The crystal structures also reveal fundamental differences in the modes of protein-protein interactions mediated by the two FP domains: the PI31 FP domain utilizes either an alpha interface or beta interface for homodimeric interaction, whereas the Fbxo7 FP domain utilizes an alphabeta interface. We perform modeling studies to show that the domain-specific structural features may dictate specific modes of inter-domain interactions. We propose that a heterodimeric interaction would be mediated by an alphabeta interface consisting of the alpha-helical and beta-sheet surfaces of the Fbxo7 and PI31 FP domains, respectively. We also discuss the structural/functional significance of various modes of FP domain-mediated protein-protein interactions. The FP domains of PI31 and Fbxo7 have the same protein fold but very different modes of protein-protein interaction.,Shang J, Huang X, Du Z J Biomol Struct Dyn. 2014 Sep 30:1-11. PMID:25266262 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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