1AL1 image
Deposition Date 1990-07-02
Release Date 1991-10-15
Last Version Date 2024-11-13
Entry Detail
PDB ID:
1AL1
Title:
CRYSTAL STRUCTURE OF ALPHA1: IMPLICATIONS FOR PROTEIN DESIGN
Biological Source:
Source Organism:
(Taxon ID: 32630)
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Observed:
0.21
Space Group:
I 41 3 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:ALPHA HELIX PEPTIDE: ELLKKLLEELKG
Chain IDs:A
Chain Length:13
Number of Molecules:1
Biological Source:
Ligand Molecules
Primary Citation
Crystal structure of alpha 1: implications for protein design.
Science 249 543 546 (1990)
PMID: 2382133

Abstact

X-ray diffraction shows the structure of a synthetic protein model, formed from noncovalent self-association of a 12-residue peptide and of sulfate ions at low pH. This peptide is a fragment of a 16-residue polypeptide that was designed to form an amphiphilic alpha helix with a ridge of Leu residues along one helical face. By interdigitation of the leucines of four such helices, the design called for self-association into a four-alpha-helical bundle. The crystal structure (2.7 angstrom resolution; R factor = 0.215) reveals a structure more complex than the design, with both a tetramer and a hexamer. The alpha-helical tetramer with leucine interior has more oblique crossing angles than most four-alpha-helical bundles; the hexamer has a globular hydrophobic core of 12 leucine residues and three associated sulfate ions. Computational analysis suggests that the hexameric association is tighter than the tetrameric one. The consistency of the structure with the design is discussed, as well as the divergence.

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Primary Citation of related structures