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Three-helix Bundle (three-helix + bundle)
Selected AbstractsStructural genomics of Caenorhabditis elegans: structure of the BAG domainACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004J. Symersky Binding of the BAG domain to the eukaryotic chaperone heat-shock protein (Hsp70) promotes ATP-dependent release of the protein substrate from Hsp70. Although the murine and human BAG domains have been shown to form an antiparallel three-helix bundle, the Caenorhabditis elegans BAG domain is formed by two antiparallel helices, while the third helix is extended away and stabilized by crystal-packing interactions. A small ,-sheet between helices 2 and 3 interferes with formation of the intramolecular three-helix bundle. However, intermolecular three-helix bundles are observed throughout the crystal packing and suggest that stable functional dimers and tetramers can be formed in solution. The structure may represent a new folding type of the BAG domain. [source] Structure of the apo form of the catabolite control protein A (CcpA) from Bacillus megaterium with a DNA-binding domainACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2007Rajesh Kumar Singh Crystal structure determination of catabolite control protein A (CcpA) at 2.6,Å resolution reveals for the first time the structure of a full-length apo-form LacI-GalR family repressor protein. In the crystal structures of these transcription regulators, the three-helix bundle of the DNA-binding domain has only been observed in cognate DNA complexes; it has not been observed in other crystal structures owing to its mobility. In the crystal packing of apo-CcpA, the protein,protein contacts between the N-terminal three-helix bundle and the core domain consisted of interactions between the homodimers that were similar to those between the corepressor protein HPr and the CcpA N-subdomain in the ternary DNA complex. In contrast to the DNA complex, the apo-CcpA structure reveals large subdomain movements in the core, resulting in a complete loss of contacts between the N-subdomains of the homodimer. [source] The structure of receptor-associated protein (RAP)PROTEIN SCIENCE, Issue 8 2007Donghan Lee Abstract The receptor-associated protein (RAP) is a molecular chaperone that binds tightly to certain newly synthesized LDL receptor family members in the endoplasmic reticulum (ER) and facilitates their delivery to the Golgi. We have adopted a divide-and-conquer strategy to solve the structures of the individual domains of RAP using NMR spectroscopy. We present here the newly determined structure of domain 2. Based on this structure and the structures of domains 1 and 3, which were solved previously, we utilized experimental small-angle neutron scattering (SANS) data and a novel simulated annealing protocol to characterize the overall structure of RAP. The results reveal that RAP adopts a unique structural architecture consisting of three independent three-helix bundles that are connected by long and flexible linkers. The flexible linkers and the quasi-repetitive structural architecture may allow RAP to adopt various possible conformations when interacting with the LDL receptors, which are also made of repetitive substructure units. [source] Structural genomics of Caenorhabditis elegans: structure of the BAG domainACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2004J. Symersky Binding of the BAG domain to the eukaryotic chaperone heat-shock protein (Hsp70) promotes ATP-dependent release of the protein substrate from Hsp70. Although the murine and human BAG domains have been shown to form an antiparallel three-helix bundle, the Caenorhabditis elegans BAG domain is formed by two antiparallel helices, while the third helix is extended away and stabilized by crystal-packing interactions. A small ,-sheet between helices 2 and 3 interferes with formation of the intramolecular three-helix bundle. However, intermolecular three-helix bundles are observed throughout the crystal packing and suggest that stable functional dimers and tetramers can be formed in solution. The structure may represent a new folding type of the BAG domain. [source] | ||||||||||