Mapping protein matrix cavities in human cytoglobin through Xe atom binding

Daniele De Sanctis, Sylvia Dewilde, Alessandra Pesce, Luc Moens, Paolo Ascenzi, Thomas Hankeln, Thorsten Burmester, Martino Bolognesi

Research output: Contribution to journalArticlepeer-review


Cytoglobin is the fourth recognized globin type, almost ubiquitously distributed in human tissues; its function is still poorly understood. Cytoglobin displays a core region of about 150 residues, structurally related to hemoglobin and myoglobin, and two extra segments, about 20 residues each, at the N- and C-termini. The core region hosts a large apolar cavity, held to provide a ligand diffusion pathway to/from the heme, and/or ligand temporary docking sites. Here we report the crystal structure (2.4Å resolution, R-factor 19.1%) of a human cytoglobin mutant bearing the CysB2(38)→Ser and CysE9(83)→Ser substitutions (CYGB*), treated under pressurized xenon. Three Xe atoms bind to the heme distal site region of CYGB* mapping the protein matrix apolar cavity. Despite the conserved globin fold, the cavity found in CYGB* is structured differently from those recognized to play a functional role in myoglobin, neuroglobin, truncated hemoglobins, and Cerebratulus lacteus mini-hemoglobin.

Original languageEnglish
Pages (from-to)1217-1221
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number4
Publication statusPublished - Apr 16 2004


  • Heme ligand diffusion
  • Human cytoglobin
  • Protein matrix cavities/tunnels
  • X-ray crystallography
  • Xe binding

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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