2nnt | pdb_00002nnt
General structural motifs of amyloid protofilaments
Structural highlights
Function[TCRG1_HUMAN] Transcription factor that binds RNA polymerase II and inhibits the elongation of transcripts from target promoters. Regulates transcription elongation in a TATA box-dependent manner. Necessary for TAT-dependent activation of the human immunodeficiency virus type 1 (HIV-1) promoter.[1] [2] 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 PubMedHuman CA150, a transcriptional activator, binds to and is co-deposited with huntingtin during Huntington's disease. The second WW domain of CA150 is a three-stranded beta-sheet that folds in vitro in microseconds and forms amyloid fibers under physiological conditions. We found from exhaustive alanine scanning studies that fibrillation of this WW domain begins from its denatured conformations, and we identified a subset of residues critical for fibril formation. We used high-resolution magic-angle-spinning NMR studies on site-specific isotopically labeled fibrils to identify abundant long-range interactions between side chains. The distribution of critical residues identified by the alanine scanning and NMR spectroscopy, along with the electron microscopy data, revealed the protofilament repeat unit: a 26-residue non-native beta-hairpin. The structure we report has similarities to the hairpin formed by the A(beta)((1-40)) protofilament, yet also contains closely packed side-chains in a "steric zipper" arrangement found in the cross-beta spine formed from small peptides from the Sup35 prion protein. Fibrillation of unrelated amyloidogenic sequences shows the common feature of zippered repeat units that act as templates for fiber elongation. General structural motifs of amyloid protofilaments.,Ferguson N, Becker J, Tidow H, Tremmel S, Sharpe TD, Krause G, Flinders J, Petrovich M, Berriman J, Oschkinat H, Fersht AR Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16248-53. Epub 2006 Oct 23. PMID:17060612[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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