1nkn | pdb_00001nkn

VISUALIZING AN UNSTABLE COILED COIL: THE CRYSTAL STRUCTURE OF AN N-TERMINAL SEGMENT OF THE SCALLOP MYOSIN ROD

spinqualitylabelsall models 1nkn, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nkn is a 4 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, RCSB, PDBsum Function [GCN4_YEAST] Is a transcription factor that is responsible for the activation of more than 30 genes required for amino acid or for purine biosynthesis in response to amino acid or purine starvation. Binds and recognize the DNA sequence: 5'-TGA[CG]TCA-3'. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Alpha-helical coiled coils in muscle exemplify simplicity and economy of protein design: small variations in sequence lead to remarkable diversity in cellular functions. Myosin II is the key protein in muscle contraction, and the molecule's two-chain alpha-helical coiled-coil rod region--towards the carboxy terminus of the heavy chain--has unusual structural and dynamic features. The amino-terminal subfragment-2 (S2) domains of the rods can swing out from the thick filament backbone at a hinge in the coiled coil, allowing the two myosin 'heads' and their motor domains to interact with actin and generate tension. Most of the S2 rod appears to be a flexible coiled coil, but studies suggest that the structure at the N-terminal region is unstable, and unwinding or bending of the alpha-helices near the head-rod junction seems necessary for many of myosin's functional properties. Here we show the physical basis of a particularly weak coiled-coil segment by determining the 2.5-A-resolution crystal structure of a leucine-zipper-stabilized fragment of the scallop striated-muscle myosin rod adjacent to the head-rod junction. The N-terminal 14 residues are poorly ordered; the rest of the S2 segment forms a flexible coiled coil with poorly packed core residues. The unusual absence of interhelical salt bridges here exposes apolar core atoms to solvent. Visualization of an unstable coiled coil from the scallop myosin rod.,Li Y, Brown JH, Reshetnikova L, Blazsek A, Farkas L, Nyitray L, Cohen C Nature. 2003 Jul 17;424(6946):341-5. PMID:12867988 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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