Structural adaptation of a thermostable biotin-binding protein in a psychrophilic environment

J Biol Chem. 2012 May 25;287(22):17951-62. doi: 10.1074/jbc.M112.357186. Epub 2012 Apr 5.


Shwanavidin is an avidin-like protein from the marine proteobactrium Shewanella denitrificans, which exhibits an innate dimeric structure while maintaining high affinity toward biotin. A unique residue (Phe-43) from the L3,4 loop and a distinctive disulfide bridge were shown to account for the high affinity toward biotin. Phe-43 emulates the function and position of the critical intermonomeric Trp that characterizes the tetrameric avidins but is lacking in shwanavidin. The 18 copies of the apo-monomer revealed distinctive snapshots of L3,4 and Phe-43, providing rare insight into loop flexibility, binding site accessibility, and psychrophilic adaptation. Nevertheless, as in all avidins, shwanavidin also displays high thermostability properties. The unique features of shwanavidin may provide a platform for the design of a long sought after monovalent form of avidin, which would be ideal for novel types of biotechnological application.

MeSH terms

  • Amino Acid Sequence
  • Carrier Proteins / chemistry*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • Temperature


  • Carrier Proteins
  • biotin-binding proteins

Associated data

  • PDB/3SZH
  • PDB/3SZI
  • PDB/3SZJ
  • PDB/3T2W
  • PDB/3T2X