1byz

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Revision as of 22:41, 24 November 2007

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spinqualitylabelsall models 1byz, resolution 0.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

DESIGNED PEPTIDE ALPHA-1, P1 FORM

Overview

A 12-residue peptide designed to form an alpha-helix and self-associate, into an antiparallel 4-alpha-helical bundle yields a 0.9 A crystal, structure revealing unanticipated features. The structure was determined, by direct phasing with the "Shake-and-Bake" program, and contains four, crystallographically distinct 12-mer peptide molecules plus solvent for a, total of 479 atoms. The crystal is formed from nearly ideal alpha-helices, hydrogen bonded head-to-tail into columns, which in turn pack side-by-side, into sheets spanning the width of the crystal. Within each sheet, the, alpha-helices run antiparallel and are closely spaced (9-10 A, center-to-center). The sheets are more loosely packed against each other, (13-14 A between helix centers). Each sheet is amphiphilic: apolar leucine, side chains project from one face, charged lysine and glutamate side, chains from the other face. The sheets are stacked with two polar faces, opposing and two apolar faces opposing. The result is a periodic, biomaterial composed of packed protein bilayers, with alternating polar, and apolar interfaces. All of the 30 water molecules in the unit cell lie, in the polar interface or between the stacked termini of helices. A, section through the sheet reveals that the helices packed at the apolar, interface resemble the four-alpha-helical bundle of the design, but the, helices overhang parts of the adjacent bundles, and the helix crossing, angles are less steep than intended (7-11 degrees rather than 18 degrees).

About this Structure

1BYZ is a Protein complex structure of sequences from [1] with CL, ACE, MRD, ETA and MPD as ligands. Full crystallographic information is available from OCA.

Reference

Packed protein bilayers in the 0.90 A resolution structure of a designed alpha helical bundle., Prive GG, Anderson DH, Wesson L, Cascio D, Eisenberg D, Protein Sci. 1999 Jul;8(7):1400-9. PMID:10422828

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