1pgy | pdb_00001pgy
Solution structure of the UBA domain in Saccharomyces cerevisiae protein, Swa2p
Structural highlights
FunctionSWA2_YEAST Cofactor for the uncoating of clathrin-coated vesicles (CCVs) by Hsp70-type chaperones (SSA1/2/3 and SSB1/2). Coat disassembly is important for fusion of vesicles with target membranes and for recycling components of clathrin coats to the cytoplasm for further rounds of vesicle formation. Binds to assembled clathrin and recruits the ATP-activated chaperone to CCVs. Stimulates the ATPase activity of the clathrin-associated Hsp70-type chaperone SSA1, which then disrupts clathrin-clathrin interactions, leading to release of the clathrin coat. In addition, prevents unproductive clathrin assembly in the cell. Also required for cortical endoplasmic reticulum inheritance.[1] [2] [3] Publication Abstract from PubMedThe SWA2/AUX1 gene has been proposed to encode the Saccharomyces cerevisiae ortholog of mammalian auxilin. Swa2p is required for clathrin assembly/dissassembly in vivo, thereby implicating it in intracellular protein and lipid trafficking. While investigating the 287-residue N-terminal region of Swa2p, we found a single stably folded domain between residues 140 and 180. Using binding assays and structural analysis, we established this to be a ubiquitin-associated (UBA) domain, unidentified by bioinformatics of the yeast genome. We determined the solution structure of this Swa2p domain and found a characteristic three-helix UBA fold. Comparisons of structures of known UBA folds reveal that the position of the third helix is quite variable. This helix in Swa2p UBA contains a bulkier tyrosine in place of smaller residues found in other UBAs and cannot pack as close to the second helix. The molecular surface of Swa2p UBA has a mostly negative potential, with a single hydrophobic surface patch found also in the UBA domains of human protein, HHR23A. The presence of a UBA domain implicates Swa2p in novel roles involving ubiquitin and ubiquitinated substrates. We propose that Swa2p is a multifunctional protein capable of recognizing several proteins through its protein-protein recognition domains. Solution structure of the ubiquitin-binding domain in Swa2p from Saccharomyces cerevisiae.,Chim N, Gall WE, Xiao J, Harris MP, Graham TR, Krezel AM Proteins. 2004 Mar 1;54(4):784-93. PMID:14997574[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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