title: Solution structure of UIM and interaction of tandem ubiquitin binding domains in STAM1 with ubiquitin.
abstract: STAM1 and Hrs are the components of ESCRT-0 complex for lysosomal degradation of membrane proteins is composed of STAM1 Hrs and has multiple ubiquitin binding domains. Here, the solution structure of STAM1 UIM, one of the ubiquitin binding motif, was determined by NMR spectroscopy. The structure of UIM adopts an α-helix with amphipathic nature. The central hydrophobic residues in UIM provides the binding surface for ubiquitin binding and are flanked with positively and negatively charged residues on both sides. The docking model of STAM1 UIM-ubiquitin complex is suggested. In NMR and ITC experiments with the specifically designed mutant proteins, we investigated the ubiquitin interaction of tandem ubiquitin binding domains from STAM1. The ubiquitin binding affinity of the VHS domain and UIM in STAM1 was 52.4 and 94.9 μM, and 1.5 and 2.2 fold increased, respectively, than the value obtained from the isolated domain or peptide. The binding affinities here would be more physiologically relevant and provide more precise understanding in ESCRT pathway of lysosomal degradation.
authors.affiliation: Biomolecular Science, University of Science and Technology, Daejeon, Republic of Korea.
authors.forename: Jongsoo
authors.initials: J
authors.lastname: Lim
authors.forename: Woo-Sung
authors.initials: WS
authors.lastname: Son
authors.forename: Joon Kyu
authors.initials: JK
authors.lastname: Park
authors.forename: Eunice Eunkyeong
authors.initials: EE
authors.lastname: Kim
authors.forename: Bong-Jin
authors.initials: BJ
authors.lastname: Lee
authors.forename: Hee-Chul
authors.initials: HC
authors.lastname: Ahn
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020080:Tandem Repeat Sequences; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D010455:Peptides; D010750:Phosphoproteins; D025801:Ubiquitin; C096164:hepatocyte growth factor-regulated tyrosine kinase substrate