Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report

Global Symmetry: Dihedral - D2  (3D View)
Global Stoichiometry: Homo 4-mer - A4 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 10.18 kDa 
• Atom Count: 931 
• Modelled Residue Count: 92 
• Deposited Residue Count: 92 
• Unique protein chains: 1

1SN9

An Oligomeric Domain-Swapped Beta-Beta-Alpha Mini-Protein

• PDB DOI: 10.2210/pdb1SN9/pdb

• Classification: DE NOVO PROTEIN
• Mutation(s): No 


• Deposited: 2004-03-10 Released: 2004-08-17 
• Deposition Author(s): Ali, M.H., Peisach, E., Allen, K.N., Imperiali, B.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.20 Å
• R-Value Free: 0.285 
• R-Value Work: 0.188 
• R-Value Observed: 0.190 

Literature

X-ray structure analysis of a designed oligomeric miniprotein reveals a discrete quaternary architecture

Ali, M.H., Peisach, E., Allen, K.N., Imperiali, B.

(2004) Proc Natl Acad Sci U S A 101: 12183-12188

• PubMed: 15302930 
• DOI: 10.1073/pnas.0401245101
• Primary Citation of Related Structures:  
  1SN9, 1SNA, 1SNE


• PubMed Abstract: 
  

The x-ray crystal structure of an oligomeric miniprotein has been determined to a 1.2-A resolution by means of multiwavelength anomalous diffraction phasing with selenomethionine analogs that retain the biophysical characteristics of the native peptide. Peptide 1, comprising alpha and beta secondary structure elements with only 21 aa per monomer, associates as a discrete tetramer. The peptide adopts a previously uncharacterized quaternary structure in which alpha and beta components interact to form a tightly packed and well defined hydrophobic core. The structure provides insight into the origins of the unusual thermal stability of the oligomer. The miniprotein shares many characteristics of larger proteins, including cooperative folding, lack of 1-anilino-8-naphthalene sulfonate binding, and limited deuterium exchange, and possesses a buried surface area typical of native proteins.

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Organizational Affiliation: 

Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
tetrameric beta-beta-alpha mini-protein	A, B, C, D	23	N/A	Mutation(s): 0

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
DBZ	A, B, C, D	L-PEPTIDE LINKING	C10 H12 N2 O3		ALA

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.20 Å
• R-Value Free: 0.285 
• R-Value Work: 0.188 
• R-Value Observed: 0.190 
• Space Group: P 2₁ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 38.939	α = 90
b = 56.172	β = 90
c = 32.32	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
MOLREP	phasing
SHELXL-97	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-03-10 
• Released Date: 2004-08-17 
Deposition Author(s): Ali, M.H., Peisach, E., Allen, K.N., Imperiali, B.

Revision History  

• Version 1.0: 2004-08-17
  Type: Initial release
  
• Version 1.1: 2008-04-29
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance