Crystal Structure of Mavicyanin from Cucurbita pepo medullosa (Zucchini)

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.193 

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Structural reorganization of the copper binding site involving Thr15 of mavicyanin from Cucurbita pepo medullosa (zucchini) upon reduction.

Xie, Y.Inoue, T.Miyamoto, Y.Matsumura, H.Kataoka, K.Yamaguchi, K.Nojini, M.Suzuki, S.Kai, Y.

(2005) J Biochem 137: 455-461

  • DOI: https://doi.org/10.1093/jb/mvi062
  • Primary Citation of Related Structures:  
    1WS7, 1WS8

  • PubMed Abstract: 

    Mavicyanin, a glycosylated protein isolated from Cucurbita pepo medullosa (zucchini), is a member of the phytocyanin subfamily containing one polypeptide chain of 109 amino residues and an unusual type-I Cu site in which the copper ligands are His45, Cys86, His91, and Gln96. The crystal structures of oxidized and reduced mavicyanin were determined at 1.6 and 1.9 A resolution, respectively. Mavicyanin has a core structure of seven polypeptide beta-strands arranged as a beta-sandwich organized into two beta-sheets, and the structure considerably resembles that of stellacyanin from cucumber (CST) or cucumber basic protein (CBP). A flexible region was not observed on superimpositioning of the oxidized and reduced mavicyanin structures. However, the Cu(II)-epsilon-O-Gln96 bond length was extended by 0.47 A, and the Thr15 residue was rotated by 60.0 degrees and O-gamma1-Thr15 moved from a distance of 4.78 to 2.58 A from the ligand Gln96 forming a new hydrogen bond between O-gamma1-Thr15 and epsilon-O-Gln96 upon reduction. The reorganization of copper coordination geometry of mavicyanin upon reduction arouses reduction potential decreased above pH 8 [Battistuzzi et al. (2001) J. Inorg. Biochem. 83, 223-227]. The rotation of Thr15 and the hydrogen bonding with the ligand Gln96 may constitute structural evidence of the decrease in the reduction potential at high pH.

  • Organizational Affiliation

    Department of Materials Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
109Cucurbita pepoMutation(s): 0 
Find proteins for P80728 (Cucurbita pepo)
Explore P80728 
Go to UniProtKB:  P80728
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP80728
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.193 
  • Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.92α = 90
b = 63.92β = 90
c = 245.35γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-11-23
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance