Structure of plastidial phosphorylase Pho1 from Barley

Experimental Data Snapshot

  • Resolution: 2.70 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.218 

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Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development.

Cuesta-Seijo, J.A.Ruzanski, C.Krucewicz, K.Meier, S.Hagglund, P.Svensson, B.Palcic, M.M.

(2017) PLoS One 12: e0175488-e0175488

  • DOI: https://doi.org/10.1371/journal.pone.0175488
  • Primary Citation of Related Structures:  
    5LR8, 5LRA, 5LRB

  • PubMed Abstract: 

    The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1 (HvPho1) for starch biosynthesis in barley endosperm, we analyzed HvPho1 protein production and enzyme activity levels throughout barley endosperm development and characterized structure-function relationships of HvPho1. The molecular mechanisms underlying the initiation of starch granule biosynthesis, that is, the enzymes and substrates involved in the initial transition from simple sugars to polysaccharides, remain unclear. We found that HvPho1 is present as an active protein at the onset of barley endosperm development. Notably, purified recombinant protein can catalyze the de novo production of α-1,4-glucans using HvPho1 from G1P as the sole substrate. The structural properties of HvPho1 provide insights into the low affinity of HvPho1 for large polysaccharides like starch or amylopectin. Our results suggest that HvPho1 may play a role during the initiation of starch biosynthesis in barley.

  • Organizational Affiliation

    Carlsberg Research Laboratory, J.C. Jacobsens Gade 4, DK-1799 Copenhagen V, Denmark.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-1,4 glucan phosphorylase
A, B
938Hordeum vulgare subsp. vulgareMutation(s): 0 
Find proteins for F2E0G2 (Hordeum vulgare subsp. vulgare)
Explore F2E0G2 
Go to UniProtKB:  F2E0G2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupF2E0G2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.70 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.218 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 229.21α = 90
b = 63.48β = 115.21
c = 148.82γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-05-03
    Type: Initial release
  • Version 1.1: 2024-01-10
    Changes: Data collection, Database references, Refinement description