4HLN

Structure of barley starch synthase I in complex with maltooligosaccharide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.173 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Structure of starch synthase I from barley: insight into regulatory mechanisms of starch synthase activity

Cuesta-Seijo, J.A.Nielsen, M.M.Marri, L.Tanaka, H.Beeren, S.R.Palcic, M.M.

(2013) Acta Crystallogr.,Sect.D 69: 1013-1025

  • DOI: 10.1107/S090744491300440X

  • PubMed Abstract: 
  • Starch, a polymer of glucose, is the major source of calories in the human diet. It has numerous industrial uses, including as a raw material for the production of first-generation bioethanol. Several classes of enzymes take part in starch biosynthes ...

    Starch, a polymer of glucose, is the major source of calories in the human diet. It has numerous industrial uses, including as a raw material for the production of first-generation bioethanol. Several classes of enzymes take part in starch biosynthesis, of which starch synthases (SSs) carry out chain elongation of both amylose and amylopectin. Plants have five classes of SS, each with different roles. The products of the reaction of SS are well known, but details of the reaction mechanism remain obscure and even less is known of how different SSs select different substrates for elongation, how they compete with each other and how their activities are regulated. Here, the first crystal structure of a soluble starch synthase is presented: that of starch synthase I (SSI) from barley refined to 2.7 Å resolution. The structure captures an open conformation of the enzyme with a surface-bound maltooligosaccharide and a disulfide bridge that precludes formation of the active site. The maltooligosaccharide-binding site is involved in substrate recognition, while the disulfide bridge is reflective of redox regulation of SSI. Activity measurements on several SSI mutants supporting these roles are also presented.


    Organizational Affiliation

    Carlsberg Laboratory, Gamle Carlsberg Vej 10, 1799 Copenhagen V, Denmark.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Starch synthase I
A
633Hordeum vulgareMutation(s): 0 
Gene Names: SSI
EC: 2.4.1.-
Find proteins for Q9M5A3 (Hordeum vulgare)
Go to UniProtKB:  Q9M5A3
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GLC
Query on GLC

Download SDF File 
Download CCD File 
A
ALPHA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-DVKNGEFBSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.173 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 153.150α = 90.00
b = 153.150β = 90.00
c = 84.960γ = 120.00
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata scaling
PHASERphasing
XDSdata reduction
ADSCdata collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-06-05
    Type: Initial release